iguana volume 10, number 4 december 2003 us$6 · a lthough the banded iguana (brachylophus...

An adult Fijian Banded Iguana (Brachylophus fasciatus) (stories on pp. 103 and 108). Photograph by Thomas Wiewandt.

IGUANAJournal of the International Iguana Society www.IguanaSociety.org

Vo l u m e 1 0 , N u m b e r 4 D e c e m b e r 2 0 0 3 U S $ 6 . 0 0

In This Issue...FEATURES:Searching for Banded Iguanas in the Lau Islands, Eastern Fiji Peter Harlow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103

The History of Banded Iguanas in United States Collections John Kinkaid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108

Introduced Iguanas in Southern Florida: A History of More Than 35 Years Josiah H. Townsend, Kenneth L. Krysko, and Kevin M. Enge . . . . .111

Species Profile: Nile Monitors (Varanus niloticus) in Florida Todd Campbell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119

The Iguana Rescue Dilemma AJ Gutman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121

If Iguanas Could Speak Andy Gogakis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127

HUSBANDRY:Green Iguana Management and HusbandryStephen L. Barten, DVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129

PROFILE:Allison Alberts: A Consumate Conservationist Tandora Grant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .142

HISTORICAL PERSPECTIVES:Iguanas of the Galápagos IslandsFranz Werner, with extensive quotations from Charles Darwin . . .145

BIOGRAPHICAL SKETCH: Franz Werner (1867–1939) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .150

BOOK REVIEW:Islands and the Sea: Essays on Herpetological Exploration inthe West IndiesRick Hudson . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151

IGUANA NEWSBRIEFS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .153EDITORIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . .157LETTER FROM THE PRESIDENT . . . . . . . . . . . . . . . . . . . . . . . . .158

Fijian Banded Iguana (Brachylopus fasciatus). See

Monitors, Green Iguanas, and Spiny-tailed Iguanas,such as Ctenosaura similis (above), have taken upresidence in Florida. See articles on pages 111 and

Visit and Join:www.IguanaSociety.org

Iguana management and husbandry. See article onpage 129.

Although the Banded Iguana(Brachylophus fasciatus) is the mostfamiliar of the two species ofBrachylophus found in the South Pacific,

its status in the wild is virtually unknown. Based onpublished and verbal distribution records, thespecies is known to occur on 34 islands in Fiji. Inaddition, it is found on four islands in Tonga andan introduced population is established on EfateIsland in Vanuatu. Currently, this iguana is theonly Brachylophus species kept in zoos outside ofAustralia and Fiji.

Banded Iguanas are still regularly reportedfrom many islands within Fiji, even inhabitedislands where cats are common and forest rem-nants are few. Popular wisdom has always declaredthat Banded Iguanas are easiest to find on the largeand heavily forested islands of Kadavu and Ovalau.However, after many weeks spent on these twoislands over many years, I have yet to find a wildBanded Iguana on either. They are certainly there;a boy with a pet Banded Iguana can be found inmany villages. Fijians still occasionally find them onforest paths, when they are clearing bush for newgardens, or when high up in an Ivi or Bau treepicking ripe, edible fruit.

In November 2000, a Portuguese bat biolo-gist on sabbatical in Fiji, Jorge Palmeirim, con-tacted me to say that he had seen three BandedIguanas is just a few hours while searching for batcaves on a tiny limestone island in eastern Fiji.Jorge had visited over 20 islands while working inFiji, and these were the only Banded Iguanas hehad seen. I was immediately excited by the possi-bility of an island where Banded Iguanas are com-mon, and, as I had worked with Jorge surveyingfor Crested Iguanas in the Yasawa Islands earlierthat year, I knew his information was accurate.Many Fijians and expatriates who have never seenan iguana often refer to the common arborealgreen skink, Emoia concolour, as an “iguana.”

In September 2002, National Trust CrestedIguana Sanctuary ranger, Pita Biciloa, and I flew tothe large inhabited island of Lakeba, 300 km east

103IGUANADecember 2003

Searching for Banded Iguanas in the Lau Islands, Eastern Fiji

Peter HarlowTaronga Zoo, Sydney

A male Banded Iguana from the island of Ovalau.

104 IGUANA Volume 10, Number 4

of Fiji’s capital, Suva. Jorge had seen the iguanas onone of the two Aiwa islands; these are small, unin-habited islands (total size 121 ha) separated by 50m of deep water, that lie about 12 km southeast ofLakeba. Like most islands in Fiji, they are owned bya traditional Fijian clan (Mataqali), and any requestto visit must first be approved by the local regionalgovernmental administrator, and then permissionobtained from the head of the Mataqali.

From Lakeba, the Aiwa islands are only a shorttrip by outboard motor boat. We landed first onthe tiny beach at Aiwa Levu, the island whereJorge had seen the Banded Iguanas. We spent onlytwo hours there, while we waited for midtide, sowe could land on the adjacent, beachless island ofAiwa Lailai. Our local Fijian guide, Cakacaka,assured us that Aiwa Lailai had even more BandedIguanas than Aiwa Levu, so we had decided tobase our three-day survey there.

A walk around the rocky limestone islandrevealed some scattered and dried iguana eggshells and many distinctive iguana scats. I soonspotted a female Banded Iguana in a low andbushy Cevua Tree (Vavaea amicorunm) over-

hanging a cliff of razor sharp limestone blades,with crashing waves below. Cevua leaves are afavorite food for Crested Iguanas, so it seemed alikely place to find a Banded Iguana. The boatmansoon returned from his reconnaissance of AiwaLailai and was shouting at us to hurry to the boat.As we waded out to the waiting boat, he assuredus that the tides, wave conditions, and currentswere now suitable for us to attempt a landing onAiwa Lailai. If we did not land within half an hour,we would miss our chance and would have to tryagain tomorrow.

At the landing site a few meters from the shoreof Aiwa Lailai, we all jumped overboard on theorders of our boatman. Two of us held the buck-ing and tossing boat in chest deep, choppy water,while the other two quickly carried our gear ashoreand tossed it on top of the undercut, two- tothree-meter high limestone cliff that encircles theisland. This included a large plastic barrel of freshwater, as both Aiwa Islands lack fresh surfacewater. As the last bag of camping gear wasremoved, the boatman jumped back in, started themotor and disappeared towards the fringing reef.

A gravid female Banded Iguana from the large inhabited island of Kadavu, where occasional sightings still occur.

He promised to return in three days — if theocean was calm. If not, he smiled as he left, wecould survive by eating the plentiful vokai(iguanas) and goats.

Pita and I undoubtedly looked puzzled, stand-ing in waist-deep water under the two-meter high,undercut cliff of razor sharp limestone that con-fronted us. The thought of having to climb overthe limestone blades that encircle the entire islandwas worrying. However, Cakacaka walked to anearby cut in the cliff, reached high, and pulleddown a sturdy tree trunk with convenient footholds cut into it. It was kept there for just this pur-pose. Happily, we clambered up this three-meter“ladder” and began the task of carrying our sup-plies to a flat area at the top of the island, wherewe set up camp.

Both Aiwa Islands have been heavily grazed bygoats for three or four decades and, although thetall forest appeared mature and diverse, the forestfloor was completely open, with only an occasionalsign of undergrowth or forest regeneration.Besides the goats, we noticed no other signs ofhuman interference; no indications of forest fires,and certainly no cats or introduced rats (althoughthe Pacific Rat, Rattus exulans, is present). This isan island of birds. Hours of searching that first day

revealed five species of pigeons and fruit-doves,including the rare (and tame) West PolynesianGround Dove (Gallicolumba stairi), PacificHarriers, and Barn Owls, plus over a dozen otherbird species and just two Banded Iguanas.

Our night surveys, however, revealed a differ-ent story. In the beam of our powerful spotlightsthe bright yellow-green belly color of BandedIguanas causes the sleeping lizards to stand outfrom the dark background vegetation. In the firstfew minutes of surveying that night, we spottedover a dozen Banded Iguanas; some as high as 18m in the forest canopy. In three nights on AiwaLailai, we counted over 200 Banded Iguanas alongour 2 km of transect lines. A wonderful result forthe first systematic survey ever.

Although not as abundant as Crested Iguanasare in optimal forest habitat on the Crested IguanaSanctuary island of Yadua Taba, Aiwa Lailaiappears to support a very healthy population ofBanded Iguanas. If Aiwa Levu has a similar num-ber of Banded Iguanas per hectare (which seemspossible, due to the similarity in vegetation andgoat grazing pressure), then these two smallislands may have a total population of 6000–8000iguanas. Small, remote and virtually inaccessibleislands are abundant around Fiji. Their remoteness


The limestone island of Aiwa Levu, seen from the neighboring island of Aiwa Lailai.

may be their greatest asset, and hopefully will con-tinue to keep feral animals, invasive plants, anddestructive agricultural practices away.

ReferencesBauer, A.M. 1988. A geological basis for some herpetofaunal dis-

junctions in the southwest Pacific, with special reference toVanuatu. Herpetological Journal 1:259–263.

Gibbons, J.R.H. and I.F. Watkins. 1982. Behavior, ecology, andconservation of South Pacific Iguanas, Brachylophus, includinga newly discovered species, p. 419–441. In: G.M. Burghardtand A.S. Rand (eds.), Iguanas of the World: Their Behavior,Ecology, and Conservation. Noyes, New Jersey.

Harlow, P.S. and P.N. Biciloa. 2001. Abundance of the FijianCrested Iguana (Brachylophus vitiensis) on two islands.Biological Conservation 98:223–231.

Zug, G. 1991. The Lizards of Fiji: Natural History and Systematics.Bishop Museum Press, Honolulu.


Our local guide, Cakacaka, on Aiwa Lailai with a femaleBanded Iguana easily captured with the aid of a very longstick.

The author with a pair of Banded Iguanas captured during night transects on Aiwa Lailai.


Illustration by John Binns.

The Banded Iguana, Brachylophus fascia-tus, was described to science in 1800, buthas been in collections of United Stateszoos for only the past four decades. One

of the most geographically isolated of all iguanaspecies, B. fasciatus occurs naturally on the FijianIsland group and has been introduced intoVanuatu and Tonga. These animals are difficult tofind in the wild, and little had been written aboutthem, other than where they were alleged to beand some very basic natural history, until late inthe 20th century. Early captives did not fare welland no captive reproduction took place until themid-1970s.

Because they are beautiful and geographicallyunique, Banded Iguanas are highly desirable dis-

play animals. The National Zoo in Washington,D.C., and zoos in Jacksonville, Sacramento,Knoxville, Dallas, and San Diego have displayedthis species since the early 1970s. Importationswere rare, although the species was not listed asendangered by the USFWS or CITES until 1980and 1981, respectively. Although some goodbehavioral and basic husbandry information hadbeen obtained, longevity was relatively short andreproduction unheard of — until the KnoxvilleZoo produced hatchlings in 1977. Fijian Iguanas,especially neonates, seem to require a great deal ofultraviolet (UV) light exposure, more than mostother iguanid species. Modern artificial lightingsystems and UV-transmitting plastics undoubtedlyhave facilitated the husbandry of this species.

The History of Banded Iguanas in United States Collections

John KinkaidAnimal Care Manager/Herpetology, Zoological Society of San Diego

(all photographs are by the author except where noted)


An adult male Banded Iguana (Brachylophus fasciatus) at the San Diego Zoo.

The San Diego Zoo’s long history of workingwith the species began in 1965, when a memberof the Zoo’s Board of Trustees, Howard Chernoff,was planning a trip to American Samoa. He askedthe Curator of Herpetology, Charles Shaw, if anyreptiles from the area were of interest. Mr. Shawreplied that it was too bad that Mr. Chernoff wasnot going anywhere near Fiji or Tonga, as it wouldbe nice to get iguanas from there. Mr. Chernoff

coincidentally met His Royal Highness, PrinceTupouto’ a-Tungi of Tonga, at a business meetingin Samoa. The Prince was pleased to donate sixiguanas to the Zoo. These arrived with great cere-mony, as they were among the first (or the veryfirst) Banded Iguanas in the country. Five moreanimals were acquired from importers in1975–1976, and the Zoo’s first hatchlings arrivedon 5 November 1981. Eager to start a viable long-


The 1965 ceremony duringwhich His Royal Highness,Prince Tupouto’ a-Tungi ofTonga (right), presented thefirst Banded Iguanas to theSan Diego Zoo. HowardChernoff, a member of theZoo’s Board of Trustees (left),was instrumental in theacquisition of these animals.Photograph courtesy of theSan Diego Zoo.

A hatchling male BandedIguana at the San Diego Zoo.

term breeding program for this species, the Zooneeded additional founders. The Orchid IslandCultural Centre in Suva, Fiji, and the FijianGovernment generously approved our plan anddonated two pairs of iguanas in 1987 and an addi-tional three pairs in 1989. No other iguanas havebeen imported into the United States since thoseanimals arrived.

With the additional founders, more experi-ence, and better knowledge of how to manageBrachylophus, the U.S. population continues todouble every decade. Almost eighty animals arenow in U.S. institutions. Over 130 hatchlings havebeen produced at the San Diego Zoo, which isnow into its fourth captive generation. An AZAstudbook and Population Management Plan aremaintained at San Diego. These exist to assist inrecommending movements, pairings, and breed-ings now and in the future. Several other U.S.zoos have also bred Banded Iguanas, and this suc-cess provides a hopeful future for these beautifullizards.

However, needs remain. First, we will contactthe Fijian government in an effort to implementpopulation surveys, habitat analyses, predator con-trol programs, and perhaps even reintroductioninto suitable areas within the historical range of thespecies. Similar programs are already in place forthe more critically endangered Crested Iguana,Brachylophus vitiensis. Also, because the U.S. pop-ulation of Banded Iguanas was established withonly twelve founders, a desperate need exists foradditional animals in order to maintain geneticdiversity. Consequently, future importations arerecommended. Finally, I would love to apply

everything we’ve learned about Banded Iguanas toa breeding program for Crested Iguanas, possiblyworking in conjunction with existing programs inFiji and Australia.


An adult female Banded Iguana on reserve at the SanDiego Zoo.

Reserve housing cages for Banded Iguanas at the SanDiego Zoo.

Banded Iguana at The Toledo Zoo. Photograph byStephanie Beiser.

Researchers have been aware of the pres-ence of non-native reptiles and amphib-ians in Florida for more than 140 years.Cope (1863) reported the small, terres-

trial Greenhouse Frog, Eleutherodactylusplanirostris (Cope), from southern Florida, andthe report of Anolis sagrei followed about 25 yearslater (Garman 1887). Since then, numerous papershave detailed the introduced herpetofauna ofsouthern Florida (e.g., Carr 1940, Duellman and

Schwartz 1958, King and Krakauer 1966, Wilsonand Porras 1983, Butterfield et al. 1997), andmore than 40 non-native species are presentlyreported. These reptiles and amphibians were ini-tially introduced and their populations are supple-mented via various routes. Some of these exoticsmay find their way into the suitable climate ofsouthern Florida as stowaways in shipments ofornamental plants and other commerce, but manyrecent introductions can be attributed to individ-

Introduced Iguanas in Southern Florida: A History

of More Than 35 YearsJosiah H. Townsend1, Kenneth L. Krysko1, and Kevin M. Enge2

1Division of Herpetology, Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611-78002Florida Fish and Wildlife Conservation Commission, Joe Budd Wildlife Field Office, 5300 High Bridge Road,

Quincy, Florida 32351

All photographs are by the senior author except where noted.


Adult female Ctenosaura similis on Key Biscayne using an old park bench as a basking site. Photograph by Joe Burgess.

uals being intentionally released by or escapingfrom reptile dealers or pet owners. As the trade inreptiles and amphibians has increased, so has thenumber of exotic species that have become estab-lished. Some of the more notable, and noticeable,of these species are three large lizards in the familyIguanidae (sensu Frost et al. 2001): the MexicanSpiny-tailed Iguana, Ctenosaura pectinata(Wiegmann), the Black Spiny-tailed Iguana, C.similis (Gray), and the Green or Common Iguana,Iguana iguana (Linnaeus).

Lizards in the genus Ctenosaura are com-monly referred to as Spiny-tailed Iguanas orCtenosaurs. They are large iguanids that typicallyhave tails ringed with rows of enlarged, spinyscales. Presently, 17 species are recognized.Ctenosaurs are found in southern Baja California,its offshore islands, and on mainland CentralAmerica from adjacent parts of Mexico to Panama(Köhler 2002; see also IGUANA 10(2):56–57and 10(3):79–81). Two of these species, C. pecti-nata and C. similis, are known to be established insouthern Florida.

Ctenosaura pectinata is native to the Pacificversant of southern Mexico. This species was firstreported in Florida by Eggert (1978), whodescribed digging up eggs and observing adultsnear Old Cutler Road in southeastern Miami-Dade County. However, Eggert (1978) erro-neously identified this population as C. similis,which was later corrected by Wilson and Porras(1983). This case of mistaken identity was the firstin a series of misidentifications involving intro-duced Ctenosaurs in Florida, as C. pectinata wassubsequently reported from Key Biscayne(Butterfield et al. 1997), Gasparilla Island (Bartlettand Bartlett 1999, McKercher 2001, McCoid2002), and from “… the streets and trees of met-ropolitan Miami” (Bartlett and Bartlett 1999).

After examining all Florida specimens ofCtenosaura in systematic collections and collectingspecimens from all known localities in southernFlorida, Townsend et al. (2003) concluded thatmost populations (including those known fromKey Biscayne and Gasparilla Island) are C. similis,and the only extant population of C. pectinataoccurs near the original Old Cutler Road site. Wevisited the Old Cutler Road site at least six timesfrom 2002–2003 and observed two adult males,six adult females, and one subadult of unknownsex living on and adjacent to a single private prop-erty east of Old Cutler Road between SW 168th

and SW 184th streets. No other C. pectinata wasseen, and local residents with whom we talkedwere unfamiliar with the lizards and unaware oftheir presence. However, one resident of theFlorida Keys related that she had observedCtenosaurs crossing Old Cutler Road while dri-ving through the area in 2002 and 2003 (H.Kavney, pers. comm.).

Ctenosaura similis is native to CentralAmerica, and is found from the Isthmus ofTehuantepec to northeastern Nicaragua and west-


Three species of iguanas have become established insouthern Florida: Ctenosaura pectinata, from near OldCutler Road (top), southeastern Miami-Dade County, andadult male Ctenosaura similis (middle), and Iguana iguanafrom Key Biscayne (bottom).

ern Panama on the respective Atlantic and Pacificversants. The extent to which C. similis hasbecome established in southern Florida is onlynow becoming clear. One of the earliest knownpopulations of C. similis in Florida occurs on KeyBiscayne. That population probably has persistedthere since at least 1979, when the Crandon ParkZoo was closed and most of the exhibit animalswere relocated to the Miami Metrozoo(Townsend et al. 2003). Since its introduction onKey Biscayne, C. similis has become well-estab-lished in Crandon Park and is being found inincreasing numbers in Bill Baggs Cape FloridaState Park at the southern end of Key Biscayne (E.Donlan and E. Golden, pers. comm.). Thisspecies also was introduced on Gasparilla Island,Charlotte and Lee counties, on Florida’s south-western Gulf Coast during the late 1970s or early1980s, when an island resident released as few asthree individuals brought back from Mexico(Krysko et al. 2003). Ctenosaura similis now

occurs on Gasparilla Island in large numbers andhas expanded its range onto the adjacent main-land and onto Cayo Costa, a small island south ofGasparilla Island. Large populations also occur onKeewaydin and Little Marco islands and withinthe boundaries of the Rookery Bay EstuarineResearch Reserve, Collier County. The latter pop-ulation was established in 1995, when aKeewaydin resident intentionally (and illegally)released 5–30 C. similis on his property (Kryskoet al. 2003). The deliberate introduction of non-native reptiles is illegal according to FloridaStatute 372.265, which specifically prohibits therelease of exotic wildlife without a permit fromthe Florida Fish and Wildlife ConservationCommission.

Confusion regarding the identities of southernFlorida’s Ctenosaurs may be attributed partially toa general similarity in the appearance of the twospecies. As adults, both C. pectinata and C. similisare large, dark-colored terrestrial lizards that may


Map of South Florida showing localities mentioned in the article.

appear striped or banded. Juveniles of both speciesare green at the time of hatching, gradually takingon the brown or black adult coloration as theymature. However, these two species may be dis-tinguished easily by using a few morphologicalcharacters that were defined by Köhler and Streit(1996) and later applied by Townsend et al.(2003) to Florida Ctenosaurs. Adult C. similis usu-ally have a gray or tan ground color with 4–12well-defined dark dorsal bands that extend nearlyto the ventral scales. Male C. similis also may takeon an orange color around the head and throatduring the breeding season. In contrast, mature C.pectinata have a black to brown ground colormarked with irregular whitish blotches, with addi-tional white coloration usually apparent in the areaof the neck and throat. These white markings maygive C. pectinata a partially banded appearance.Both C. similis and C. pectinata have tails that areringed with rows of enlarged spiny scales, orwhorls, that are separated by smaller smooth scales,or intercalaries — but differ in the number ofintercalaries that separate the whorls. This is mostapparent near the base of the tail. Ctenosaura sim-

ilis has whorls separated by two rows of intercalar-ies and C. pectinata has whorls separated by threerows of intercalaries. Florida C. similis also tend tohave very few (usually zero) small dorsal scalesbetween the posterior end of the dorsal crest andthe anterior end of the caudal crest, whereasFlorida C. pectinata usually has 7 or 8 (range0–20) dorsal scales between crests (Townsend etal. 2003).

Currently, C. pectinata appears to be restrictedto a single small area around Old Cutler Road, andoccurs in low numbers there despite having beenintroduced at least 25 years ago. Expansion of thispopulation may have been limited by natural andman-made geographic barriers, including a canalto the north, construction in the early 1980s of alarge corporate headquarters to the south,


Adult female (right) and an adult male andfemale (below) Ctenosaura pectinata near OldCutler Road, southeastern Miami-Dade County.

(below) Adult maleCtenosaura similis,

Key Biscayne.

Biscayne Bay to the east, and Old Cutler Road tothe west. A large area directly to the south of thecurrent population was developed since the time itwas reported by Wilson and Porras (1983), aprocess which may have reduced the numbers ofC. pectinata to the low numbers seen today. Incontrast, C. similis has been an exceedingly suc-cessful invader, becoming well-established andexpanding its range in a number of Florida locali-ties. Site fidelity associated with Ctenosaura uti-lization of holes or other refugia may slow theprocess of range expansion beyond the original siteof introduction. Nonetheless, neither species of

Ctenosaura has been nearly as successful as aninvader as their familiar relative, the Green orCommon Iguana (Iguana iguana).

Iguana iguana is one of the most popular rep-tiles in the pet trade, with over 1.14 millionimported into the United States in 1995 alone,and represents about 45% of all reptilian imports(Hoover 1998). Iguana iguana has a wide nativerange and is found at low elevations on the main-land from Sinaloa, Mexico south to Ecuador onthe Pacific versant and Veracruz, Mexico to south-ern Brazil on the Atlantic versant, as well as onsome Central and South American coastal islands


Juvenile Ctenosaura similis, Key Biscayne.

Adult male Iguana iguana, Key Biscayne.

Three Green Iguanas (Iguana iguana) sit at canal’s edge,Key Biscayne.

and throughout the Lesser Antilles. In the UnitedStates, I. iguana has been introduced in southernFlorida and Hawaii (McKeown 1996). Iguanaiguana was first reported in southern Florida byKing and Krakauer (1966), who indicated thatiguanas could be found on Key Biscayne, Hialeah,Coral Gables, and near the Miami InternationalAirport. Iguana iguana has since become estab-lished at least as far north as Palm Beach Countyon the Atlantic Coast and Lee County on the GulfCoast (Bartlett 1980, Bartlett and Bartlett 1999,Townsend et al. 2002, Krysko et al. in press), andas far south as Stock Island in the Florida Keys,Monroe County. In all likelihood, this species ismuch more abundant in southern Florida thanpreviously reported in the literature. The largestpopulations of I. iguana probably occur in easternMiami-Dade County on Key Biscayne, in FairchildTropical Garden, and Matheson Hammock Park,but these lizards are now found at localitiesthroughout the county and have been sightednumerous times in Everglades National Park(Meshaka et al. 2000).

In Florida, I. iguana usually is found nearwater, often in trees or on embankments border-ing canals and lakes, or even basking on lawns orpavement in urban and suburban areas. Juveniles

and adults are strictlyherbivorous. InFlorida, iguanas eat awide variety of bothexotic ornamentals andnative plants (seeIGUANA10(3):94–95). Iguanaiguana on KeyBiscayne nests in sandyareas, often with multi-ple females utilizing a

single small area. Most hatchlings appear duringJuly and August. Relatively few predators of juve-niles occur in the urban and suburban areas ofsouthern Florida, a factor that may lead to rapidgrowth in any introduced I. iguana populationthat contains multiple reproducing females. Lackof predators and abundance of food are some ofthe primary explanations for the very high popula-tion densities of I. iguana found in southernFlorida.

Bill Baggs Cape Florida State Park (CFSP)occupies 174 ha at the southern end of KeyBiscayne, almost all of it consisting of coastalstrand habitat dominated by Saw Palmetto(Serenoa repens) or coastal hammock dominated byButtonwood (Conocarpus erectus) and Sea Grape(Coccoloba uvifera). In 2003 alone, CFSP staffremoved over 500 Green Iguanas (E. Donlan,pers. comm.). However, thousands of iguanas liveon Key Biscayne outside of CFSP, and, when an I. iguana is removed from the grounds of CFSP,other iguanas from outside the park simply movein and take up available space. Low winter tem-peratures appear to be a major factor limiting thenorthern expansion of I. iguana in Florida; how-ever, a freeze in Miami-Dade County during thewinter of 2002–2003 did little more than tem-


An obviously gravid female Iguana iguana pauses whileexcavating her nest at Key Biscayne. Photographs by EstherM. Langan.

porarily reduce numbers (see IGUANA10(3):98). Interestingly, many I. iguana havelearned to seek shelter in burrows or under build-ings, and we have observed I. iguana takingrefuge under water, exposing only their snouts forbreathing, to escape extremely cold temperatures.

Another large iguanid, the HispaniolanRhinoceros Iguana or Cyclura cornuta(Bonnaterre), was reported in very small numbersin the vicinity of the Miami Seaquarium onVirginia Key and also possibly on Key Biscayne(King and Krakauer 1966). A few individuals ofthis species escaped from an exhibit at theSeaquarium and are purported to have repro-duced in small numbers (Bartlett and Bartlett1995). However, we have not observed thisspecies in the wild, and no specimens from Floridaare known to have been deposited in any system-atic collections.

With the ranges and population sizes ofCtenosaura similis and Iguana iguana continuingto grow and the population of C. pectinata per-sisting for over 25 years, these species obviouslyhave become a permanent part of the dynamicherpetofauna of southern Florida. These threelizard species are only a few of the growing num-ber of introduced reptiles and amphibians that callsouthern Florida home. This number seems to beincreasing as quickly as researchers are able toinvestigate each new report of a possible intro-duced species. Without importers and pet ownersshowing greater responsibility and stricter enforce-

ment of Florida state laws regarding the release ofexotic animals, what remains of the native her-petofauna in southern Florida stands a goodchance of being displaced by exotic species in thenear future.

AcknowledgementsWe thank Kevin Kirwin and Ernest Link of

Crandon Park; Elizabeth Golden and Ellen Donlanof Bill Baggs Cape Florida State Park; ReggieNorman, Ken Alvarez, Chris Angel, and PattyMiddleton of Gasparilla Island State Park; andSteve Bertone of Rookery Bay Estuarine ResearchReserve for facilitating field work at their respectiveparks and for providing much useful information.Helen Kavney provided additional information.


A Buttonwood Tree(Cornocarpus erectus)provides food and a place tobask for this Green Iguana(Iguana iguana) on WatsonIsland in Miami. Photographby Joe Wasilewski.

A Green Iguana (Iguanaiguana) makes itself at home

on a Coconut Palm (Cocosnucifera) in downtown

Miami. Photograph by JoeWasilewski.

Literature CitedBartlett, R.D. and P.P. Bartlett. 1995. Iguanas. Barron’s Educational

Series, Hauppauge, New York. 88 pp.

Bartlett, R.D. and P.P. Bartlett. 1999. A Field Guide to FloridaReptiles and Amphibians. Gulf Publishing Company, Houston,Texas. 280 pp.

Butterfield, B.P., W.E. Meshaka, Jr., and C. Guyer. 1997.Nonindigenous amphibians and reptiles, pp.123–138. In: D.Simberloff, D. C. Schmitz, and T. C. Brown (eds.), Strangers inParadise: Impact and Management of Nonindigenous Speciesin Florida. Island Press, Washington, D.C.

Carr, A.F., Jr. 1940. A contribution to the herpetology of Florida.University of Florida Publications, Biological Sciences 3:1–118.

Cope, E.D. 1863. On Trachycephalus, Scaphiopus, and otherAmerican Batrachia. Proceedings of the Academy of NaturalSciences of Philadelphia 15:43–54.

Duellman, W.E. and A. Schwartz. 1958. Amphibians and reptilesof southern Florida. Bulletin of the Florida State Museum,Biological Sciences 3:181–324.

Eggert, J. 1978. The invasion of the Wish Willy. Florida Wildlife31(5):9–10.

Frost, D.R., R. Etheridge, D. Janies, and T.A. Titus. 2001. Totalevidence, sequence alignment, evolution of polychrotid lizards,and a reclassification of the Iguania (Squamata: Iguania).American Museum Novitates (3343):1–38.

Garman, S. 1887. On West Indian reptiles. Iguanidæ. Bulletin of theEssex Institute 19:1–26.

Hoover, C. 1998. The U.S. Role in the International Live ReptileTrade: Amazon Tree Boas to Zululand Dwarf Chameleons.TRAFFIC North America, Washington, D.C. 59 pp.

King, F. W. and T. Krakauer. 1966. The exotic herpetofauna ofsoutheast Florida. Quarterly Journal of the Florida Academy ofSciences 29:144–154.

Köhler, G. 2002. Schwarzleguane. Lebensweise, Pflege, Zucht.Herpeton, Offenbach. 142 pp.

Köhler, G. and B. Streit. 1996. Notes on the systematic status oftaxa acanthura, pectinata, and similis of the genus Ctenosaura(Reptilia: Sauria: Iguanidae). Senckenbergiana Biologica75:33–43.

Krysko, K.L., K.M. Enge, J.H. Townsend, E.M. Langan, S.A.Johnson, and T.S. Campbell. In press. New county records ofamphibians and reptiles from Florida. Herpetological Review.

Krysko, K.L., F.W. King, K.M. Enge, and A.T. Reppas. 2003.Distribution of the introduced Black Spiny-tailed Iguana(Ctenosaura similis) on the southwestern coast of Florida.Florida Scientist 66:74–79.

McCoid, M.J. 2002. Geographic distribution: Ctenosaura pectinata.Herpetological Review 33:321.

McKeown, S. 1996. A Field Guide to Amphibians and Reptiles inthe Hawaiian Islands. Diamond Head Publishing, Los Osos,California. 172 pp.

McKercher, E. 2001. Ctenosaura pectinata (Iguanidae) on GasparillaIsland, Florida: colonization, habitat use and interactions withGopherus polyphemus. M.S. Thesis, University of Florida,Gainesville, Florida. 117 pp.

Meshaka, W.E., Jr., W.F. Loftus, and T. Steiner. 2000. The her-petofauna of Everglades National Park. Florida Scientist63:84–103.

Townsend, J.H., K.L. Krysko, and K.M. Enge. 2003. The identityof Spiny-tailed Iguanas, Ctenosaura, introduced to Florida, USA.Herpetozoa 16:67–72.

Townsend, J.H., K.L. Krysko, A.T. Reppas, and C.M. Sheehy III.2002. Noteworthy records of introduced reptiles and amphib-ians from Florida, USA. Herpetological Review 33:75.

Wilson, L.D. and L. Porras. 1983. The ecological impact of man onthe south Florida herpetofauna. University of Kansas Museumof Natural History, Special Publication (9):vi + 89 pp.


A Green Iguana (Iguanaiguana) shares the shorelinewith White Ibises (Eudocimusalbus) in a Miami park.Photograph by Joe Burgess.

Green Iguanas, such asthis juvenile, are a

common sight in andaround the Colobus

Monkey exhibit at theMiami Zoo. Photograph

by Carole Saucier.


Varanidae is a monotypic family of about 50species of Old-World lizards containing only thegenus Varanus. These generally large, intelligent, car-nivorous lizards occur in Africa, Australia, andSoutheast Asia in habitats ranging from deserts andsavannahs to tropical rainforests and mangroves. Atleast one large species has gained a foothold in theWestern Hemisphere and may represent a consider-able threat to native wildlife populations.

The Nile monitor, Varanus niloticus, ranges nat-urally throughout central and southern Africa. Twosubspecies, the Common (V. n. niloticus) and Ornate(V. n. ornata) Nile Monitor were once recognized,but full species status was recently awarded themboth. The former has a blue tongue and 6–9 golddorsal bands and the latter has a pinkish tongue and3–5 dorsal bands. The oft-used vernacular name“Money Monitor” refers to its coin-sized, gold dor-sal spots. Reaching a maximum total length of overtwo meters (usually about 1.5 m) and a maximumweight of over 10 kg (usually 5–8 kg), this is one of

the largest lizard species on Earth. They often live tobe 10 or more years old, but reach sexual maturity inunder three years, and larger, older females may lay60–80 eggs in a clutch. In Kenya, they reach densi-ties of 40–60 lizards/km2. As a result of their largesize, high reproductive rates, and abundance, thisspecies is heavily exploited for meat and leather, andis considered valuable in its native lands — but thisspecies is particularly unwelcome outside its nativerange.

At least 13 years ago, this species became estab-lished in Cape Coral, a sprawling coastal residentialarea near Ft. Myers in southwestern Florida. In the1950s, the wetlands of this region were ‘reclaimed’for development by using the spoils dug from anover 400-mile-long network of deep canals.Additional aquatic and wetland habitats were cre-ated in the areas’ numerous golf courses. Moreover,Cape Coral is fringed by extensive mangroves andremote barrier islands. These freshwater canals,lakes, and wetlands, combined with a low density ofhomes and remote coastal mangroves, provide idealconditions for the establishment and spread of thisspecies. The origin of the introduced lizards remainsunknown, but the extent of the problem becameapparent in 2000 due to the efforts of Kraig Hankins(City of Cape Coral), Kenneth Krysko (University ofFlorida), and Kevin Enge (Florida Fish and WildlifeConservation Commission). This species currentlyoccupies over 50 km2 of residential areas, canalbanks, and surrounding pine flatwoods, mangroves,

SPECIES PROFILE: Nile Monitors (Varanus niloticus) in Florida

Todd CampbellDepartment of Biology, University of Tampa

This 5-foot, 15-pound Nile Monitor was captured at a res-idence in Cape Coral.

Nile Monitors construct burrows in the banks of over 400miles of canals in Cape Coral.

The remote pine flatwoods of the Charlotte Harbor BufferPreserve provide valuable habitat for native species, butalso may be a corridor for expansion of Nile Monitors.


barrier islands, and other natural habitats in andaround Cape Coral.

The impact of this species on native wildlife islargely anecdotal at this time, but in southwesternCape Coral, pets have been disappearing, feral catsare relatively rare, and residents tell tales of monitorseating rabbits in their yards and goldfish in theirponds. In their native range, Nile Monitors are gen-eralist carnivores that will take snails, spiders, crus-taceans, insects, fish, amphibians, reptiles, birds, birdeggs, and mammals. Their diet changes with agefrom crabs and other invertebrates to vertebratesand carrion. They can dig their own burrows, butprefer to sequester an existing burrow after makinga meal of the resident. These intelligent, stealthypredators are at home above and below ground, inwater, and in trees. The potential for impact onnative species is not yet known, but a few legallyprotected taxa may be particularly vulnerable.

Cape Coral has a notoriously large population ofBurrowing Owls, a small species of terrestrial owlthat digs burrows in open habitats and canal banks.The eggs and hatchlings of the Gopher Tortoise,another burrowing species, may be vulnerable toadult monitors. Nile Monitors compete with andconsume Dwarf Crocodiles in their native haunts,suggesting that American Alligators could be at risk.Nile Monitors also harbor introduced parasites thatcould be transmitted to other vertebrates and evenhumans.

In July 2003, I initiated a research program atthe University of Tampa with funding from theCharlotte Harbor National Estuary Program and theNational Fish and Wildlife Foundation. With the helpof local residents, lizards are being located, trapped,and ethically euthanized to obtain information abouttheir current geographic distribution, density, naturalhistory, reproductive cycle, diet, and impact on native

species — and to assess the potential for rangeexpansion and the possibility of eradicating thisspecies from the area. Total eradication may proveunfeasible, but the knowledge gained will assist inmanaging populations of this and other introducedcarnivorous lizards in Florida and elsewhere.

ReferencesBennett, D. 1995. Little Book of Monitor Lizards. Viper Press.

Burridge, M. J., L. A. Simmons, and S. A. Allan. 2000.Introduction of potential heartwater vectors and other exoticticks into Florida on imported reptiles. Journal of Parasitology86:700–704.

de Buffrénil, V. and G. Hémery. 2002. Variation in longevity,growth, and morphology in exploited Nile Monitors (Varanusniloticus) from Sahelian Africa. Journal of Herpetology36:419–426.

de Buffrénil, V., C. Chabanet, and J. Castanet. 1994.Preliminary data on dimensions, growth and longevity of mon-itor lizard Varanus niloticus in Lake Chad area. CanadianJournal of Zoology 72:262–273.

Lenz, S. 1995. The biology and ecology of the Nile Monitor,Varanus niloticus (Linnaeus 1766) in Gambia, West Africa.Mertensiella 5:1–256 (in German).

Losos, J. B. and H. W. Greene. 1988. Ecological and evolution-ary implications of diet in monitor lizards. Biological Journal ofthe Linnaean Society 35:379–407.

Luiselli, L., G. C. Akani, and D. Capizzi. 1999. Is there any inter-specific competition between Dwarf Crocodiles (Osteolaemustetraspis) and Nile Monitors (Varanus niloticus) in the swampsof central Africa? Journal of Zoology, London 247:127–131.

All photographs by the author.

The author with the first Nile Monitor to trapped in hisattempt to eradicate the species from Cape Coral.

Nile Monitors patrol regular pathways and excavate bur-rows along artificial canal banks in Cape Coral, but alsocross the canals and enter the surrounding natural man-grove habitats in the Charlotte Harbor Buffer Preserve.

According to the Humane Society of theUnited States (2001), more than 3.9 mil-lion households in the U.S. keep one ormore reptiles or amphibians as pets.

Approximately 18% of these are Green Iguanas(720,000). Data collected between 1989 and1997 indicate that an average of 381,000 GreenIguanas are imported each year, 566,000 in 1997alone. Based solely on anecdotal evidence, manyrescuers have long believed that as many as 90% ofpet Green Iguanas die within a year. If more thanhalf of the total pet iguana population is replacedeach year, this tragic assumption is probably well-grounded in truth.

Properly tended, a Green Iguana can live for20–30 years, but, undoubtedly, few reach such a

venerable age. Again, based on anecdotal evidence,I believe that only a tiny fraction of those GreenIguanas that manage to survive their first year incaptivity actually live out their potential life spansin the hands of a single caretaker. What becomesof the rest of them? On a bad day, when I aminundated with phone calls and e-mail messages, Ifeel as if every last one of those survivors comespast my door.

Why do people give up iguanas?Aside from the “my iguana has gotten too

big” and the “I can’t provide my iguana withenough attention,” calls, most of the otherinquiries I receive asking for help with GreenIguana rescues begin with, “I have an awkward

The Iguana Rescue DilemmaAJ Gutman

West Hartford, CTAll photographs by Carole Saucier except where indicated.


Bronte (formerly Emily) has been at the Iguana Sanctuary for the last five of his approximately 16 years.

and very unusual situation ...” While the situationmay indeed be awkward for the person on theother end of the line, after many years of rescuingall manner of reptiles, the stories are all too pre-dictable for me. In fact, if you list the principalcharacters involved, I can generally fill in the sce-nario with great accuracy.

We’re getting divorced and we need a home for theiguana.

I’m newly married and my spouse feels we need —(and the classic variation) I’ve been married for ayear and my spouse feels we need …

My son/daughter is leaving for college and we need …

I’m moving and my new landlord insists that wefind …

Those that are my least favorites require imme-diate attention:

My tenant just moved out and left behind his iguana.

There’s an animal in the plum tree in my frontyard. Can you come and get it?

Occasionally, I encounter a novel variation(I’ve just been evicted, my spouse has been incar-cerated, I found this on the railroad tracks), but,ultimately, everyone wants help and they want itimmediately. If I can’t take their animal right away,the iguana is likely to be released. A fortunate feware brought to me by Animal Control.

Boy or a Girl?“The iguana is in good health — but I don’t

know if it’s a boy or a girl.” Not surprisingly, thosewho cannot tell the difference between a male and

a female iguana lack the wherewithal to judge theanimal’s state of health. No, a hot rock and bowl oflettuce don’t cut it. Anyone with a truly healthyiguana knows that proper iguana nutrition is a four-letter word: W-O-R-K. Proper care requires a com-plex orchestration of planning, shopping, andpreparation — and there aren’t any shortcuts.

Most of the iguanas that come to me (includ-ing those in “good health”) are in fact quite ill. Isee all degrees of stunting, emaciation, deformity,and disease, most of them resulting from improperlighting or nutrition and the attendant stress.Those that are unadoptable and stay with me per-manently are generally the most physically handi-capped and ill-tempered, the “FLKs” and the“grumps.” “FLK” or “Funny-Looking-Kid” is atechnical term that my husband learned in medicalschool to denote individuals with genetic aberra-tions leading to physical abnormalities. I also applyit to my animals with nutrition-related and con-genital deformities.


“It’s in pretty good shape.” Mina was actually all right —for an abandoned, stunted animal with only one dorsalspine that hadn’t rotted off, four digits that hadn’t beenamputated by persistent constriction bands, an oozinginfection in her upper chest and dewlap, and a couple ofvertebral fractures.

Tatiana is the quintessential “Funny-Looking Kid.”Abandoned at a pet shop, she was purchased by anotherrescuer and eventually brought to me for further rehabilita-tion. Despite all the twists in her back and tail, she has noproblem walking or climbing.

The “grumps” are another fairly uniformgroup — they tend to be larger, older females thatare a bit snappish and just won’t tolerate handling.These animals often are returned to me after aninitial placement because they have been aggressivetoward another iguana or people find themselvesunable to relate to such an animal. From experi-ence, I know that these “girls” will acclimate withtime, but it’s a process that requires patience —sometimes years rather than months, and few peo-ple have the stamina to outlast their grumpiness.

The aggressive male iguanaAny reasonable program of behavior modifica-

tion should begin with an assessment of how theworld must appear from the subject’s perspective.My work rehabilitating iguanas began with thisprinciple and the assumption that the problems ofevery aggressive iguana could be addressed.

I have been privileged to gain a wealth ofinsight into iguana behavior from animals withwhich I have worked over the years, but nonechallenged my initial beliefs until I met Kurosawa.Kurosawa was a 13-year-old male that had beenraised by an adoring and attentive owner. He hadbeen neutered at the age of seven when he beganto be quite aggressive, and this seemed to calmhim for a time. But, after he left 42 stitches in hisowner’s arm, she was considerably relieved that Iwas willing to take on her beloved “bad boy.”Large but comparatively thin upon arrival,Kurosawa immediately challenged one of my other

male Green Iguanas, lost the scrap and then settledin peacefully and began to eat — and eat and eat.Several months and several pounds later, Kurosawawas no longer peaceful. He was terrorizing everyother iguana that crossed his path. Then he startedto challenge me. Initially, his challenges weremerely aggressive posturing and gaping, but thisquickly progressed to a stage in which he beganleaping across the room to try and attack me. Mygreat experiment had failed and, in consultationwith Kurosawa’s previous owner, we decided thatthe only reasonable choice was euthanasia. In ret-rospect, I am tempted to believe that he had sim-ply been biding his time until he had become bigenough to once again assert himself.

“My iguana needs a better home than I canprovide.”

What are the options for placement? Very few.Zoos, nature centers, and animal welfare groups(HSUS, SPCA) constantly receive calls regardingunwanted pet iguanas, and they inevitably referthese callers to me or others among a handful of


Odessa fits the profile of the large, aggressive female. Keptwith other iguanas that match her in size, she has adaptedwell socially. Odessa was left behind when her ownersmoved out of their apartment; she was mistaken as a maleby several other rescuers before she came to the Sanctuary.

Kurosawa during a visit from his previous owner, he hadplumped up but had not yet become unmanageablyaggressive. Photograph by Ron Miyashiro.

individuals willing to deal with reptiles. All of ustend to be constantly overwhelmed and under-funded. Quite simply, no formal organization inthis country is willing and able to cope with theever-increasing number of unwanted pet reptiles.

“I’m going on vacation to Puerto Rico;couldn’t I just release my iguana there?” No!!!

Over the years, hundreds, likely thousands, ofGreen Iguanas have been released into the wild inthe state of Florida and, in most instances, they areconsidered pests. An article in the Miami Heraldonce addressed the feral iguana problem inFlorida, and my telephone number was listed as acontact for the International Iguana Society.Although I live in Connecticut, I was deluged withcalls from irate Miami residents demanding that Icome immediately to fetch Green Iguanas fromtheir ornamental shrubbery (see also the article onp. 111).

Green Iguanas are not native to Florida and,in places like the Keys, they compete directly withnative animals for a limited supply of vegetation.In the Lesser Antilles, Green Iguanas not only out-reproduce, but are known to have hybridized withnative Iguana delicatissima. Puerto Rico is a dif-ferent case still; native Cyclura pinguis was extir-pated from the island long ago, and an introducedGreen Iguana population has become firmly estab-lished. Could a captive-raised Green Iguana sur-

vive in the wild? Yes, obviously better than wemight have imagined. Nevertheless, the argumentremains that captive-held animals are likely to havean intestinal flora, other bacteria, and external orinternal parasites that do not occur in the wild —and which may adversely affect wild populations ofnative animals with which they come into contact.

A frightening alternativeFor a brief time, I was almost able to delude

myself that the iguana rescue traffic was slowing alittle. An occasional caller who, when told that Iwas unable to take an iguana immediately, wouldask me if had heard anything about a place that I’llcall the “Alternative Reptile Institution” (ARI),which would supposedly accept any healthy,unwanted reptile for a fee. I really hadn’t heardanything at all about the ARI, until another res-cuer asked me for assistance with an extensive res-cue effort.

I discovered that this was where the remainderof the rescue traffic from my area had beendiverted. Countless Green Iguanas had been takenin by the ARI. Some of the healthy ones wereimmediately resold, but countless others had died.Those that I was able to rescue had been housedtogether in a fairly large enclosure heated with asingle inaccessible bulb, no functional ultravioletlight, dirty water, and no food. The largest iguanawas perched in the only available basking spot and

would not allow any ofthe others to approachthe food on those rareoccasions when anywas available. All of theanimals were emaci-ated, dehydrated, cov-ered with mites, and invarious states of furtherdisrepair. Some hadopen wounds and bro-ken bones from recentinjuries, others hadburns and secondaryinfections.

Among the ani-mals I was able to res-cue from the ARI wasa small RhinocerosIguana that had beenthere for about a year.She had been housed


This rescued Green Iguana had extensive burns across her pelvis and rear limbs. She wasable to heal once her mite infestation had been cleared.

with two large males and another small female ofher species. I was immediately drawn to herbecause she came over to the glass and looked mestraight in the eye — a prototypical FLK. She hada spinal scoliosis that left her looking like a reptil-ian version of a water buffalo. Her emaciated pelviswas jutting out prominently and, even through theglass, I could see the top off her head crawlingwith red mites. She also had the most awkwardmethod of locomotion, with her legs sprawlinguncontrollably in every direction. I was laterinformed that this type of movement is called“hypertonus,” and is comparable to the humancondition called cerebral palsy.

The Rhino enclosure was large and had clearlybeen quite impressive when new, but it had notbeen maintained. The pool was empty and thesubstrate filthy. The temperature gradient wasappropriate and even a bit of UV light intruded —but not in a location accessible to the animals. A

platter of dandelions, which a volunteer had justpicked outside, was available, but the two smallfemales were consistently kept from feeding by thetwo larger males.

I was permitted to take both females. Thecrooked one (Dolly) was considered too unattrac-tive for display, while the other (Loretta) bore clearsigns of a developing infection. Both animals, ateight years of age, were barely half the size of thesix-year old Rhino female that has been with mesince she was a hatchling. Dolly, who had appar-ently been left at the ARI only a year earlier, blos-somed quickly once she had her own exclusivebasking spot and a “bottomless” bowl of nutri-tious food. Although her movements remain awk-ward, she is able to climb “handicap ramps” andhas been accepted by my other Rhinos.

Loretta’s recovery proved to be much morechallenging. Blistering that had been present onher legs and trunk when I took her had erupted


This animal had a broken rear limb with an open wound, likely caused by a bite from a cagemate. In the absence of anymedical treatment, the wound developed a huge abscess.

into extensive lesions, which took a very long timeto heal and left extensive scarring. Her growth andsocialization have been much slower, but I suspectshe also will integrate comfortably into the Rhino“family” in time.

The dilemmaSo what’s the dilemma? I truly love the work

that I do and I find it enormously fulfilling, but it’salso exhausting and unceasing. I’ve finally draggedmyself through the endless process of becoming anot-for-profit organization and have been offeredweb space by a number of people. Yet, my great-est fear in creating a greater visibility for reptile res-cue is that I will be completely inundated witheven more unwanted animals without being ableto obtain any help or funding.

In September, I was invited to attend an expo-sition for various animal rescue groups. I was eagerto see how people working with other types of ani-mals functioned. Unfortunately, I was obliged toback out of the engagement at the last minutewhen I discovered that I was required to pay a feefor a table as well as provide volunteers to assist insetting up. A fee? Most people giving up iguanashave little interest in providing for their care.Those who adopt animals will sometimes make adonation, but just as often need their resources topurchase equipment and food for their newcharges. Volunteers? The occasional person hasthreatened to volunteer, but a closer look at thework reveals its generally unglamorous nature and

I’ve never had anyone show up and actually do anywork. I thought it absurd to be asked to pay forthe privilege of facing my usual dilemma.

So, how can the problem of unwanted GreenIguanas be properly addressed? Do we really needto ban the sale of these animals in pet shops?Require licensing? Ban ownership? Or perhapsinsist that publicly supported animal welfare orga-nizations take on the problem? Among theHSUS’s stated charter purposes is to “protect allliving things, especially animals.” I was appalled toread their extensive documentation on the reptilepet trade and related “humane concerns,” know-ing that so little is being done by that organiza-tion. Even less impressive is the total lack of inter-est from a very large portion of the reptile petindustry, which directly benefits from the sale ofthese animals.

A glimmer of lightAnother recent rescue involved two Green

Iguanas abandoned on the doorstep of a cat shel-ter. The stunted and battered little animals were inno way unusual, but the response of the sheltermanager was encouraging. She knew that shelacked the knowledge to care for the iguanas, yetshe recognized that they deserved her attention,and she undertook the process of tracking downsomeone who did. Between the time that shecalled me in the morning and when we met at aparking lot that same afternoon, she had clearlydone some research. As I was transferring the ani-mals from her car to mine, she was answeringquestions for a curious passerby: “No, they don’tmake good pets. They’ll burn themselves on a hotrock and they need a wide variety of vegetablesand fruits.”

I don’t know what the long-term solution willbe — but I invest a considerable portion of thetime and effort left after taking care of animals topromote education on proper iguana husbandry.And at least some of the most critical informationseems to be filtering through.

ReferenceFranke, J. and T.M. Telecky. 2001. Reptiles as Pets: An Examination

of the Trade in Live Reptiles in the United States. The HumaneSociety of the United States, Washington, DC.


Despite a crooked spine and extremely awkward locomo-tion, Dolly has been well-received by the other members ofthe Rhino “family.”


I saw, in web unbroken,Its history outwroughtNot as the loud had spoken,But as the mute had thought.

—Thomas Hardy

Someone once asked me why iguanas are mute.I skipped the whole vocal cords thing and gave himwhat I thought was a most appropriate answer.“Iguanas,” I said, “are mute because, if God hadgiven them a voice, we wouldn’t be able to hear our-selves think for their screaming and crying…”

I was born and raised in Athens, Greece and myparents were considerate enough to introduce me tothe wonders of animal life from an early age.Growing up in an environment filled with cats, dogs,

reptiles, and birds, I learned how to love life itself. Infact, I am quite certain that I learned how to lovehumans from my interactions with animals.

When I was 15, one of my Red-eared Sliders(Trachemys scripta) broke the right side of her shell ina fall from her terrarium. I was devastated. I took herto my dog vet, who apparently had no idea aboutreptiles and couldn’t do a single thing to help her. Ibegan searching for a reptile vet in Greece — butcouldn’t find one. After a rigorous search, I came toa sad discovery. I was completely alone. Not a singleGreek veterinarian worked on reptiles! The petshops, although full of reptiles, didn’t know the firstthing about herp care. The picture wasn’t right —but I wasn’t going give up on my turtle. I began pur-chasing foreign literature on pond turtles in order to

If Iguanas Could SpeakAndy Gogakis

Athens, Greece

Andy Gogakis with his pet iguana, Eric. Photograph by Lucas Liaskos.


cure mine myself.That’s when it hit me.Everything I had beendoing in regard to tur-tle husbandry wasutterly wrong.

Nobody in Greecewas interested in rep-tiles. When confrontedwith the question:“What am I to do withmy sick pet?” every-one, including manyvets and my parents,responded: “Let it dieand buy a new one; it’snot like you are dealingwith a dog.” For cryingout loud! We are talk-ing about a living,breathing entity here.Come on, show somecompassion here, peo-ple. I was confrontedby the same responsefrom everyone I talkedto about the BlueIguana extinction issue.Phrases like “Whocares?” or mere grins were enough to make any con-siderate person angry. Suffice it to say, I cured thepoor creature myself. Ten years after her accident sheis doing well, although her shell never recoveredcompletely (turtles have a very slow healing rate).

More serious problems arise when it comes toiguanas. Greece has to be the only country in theworld that treats lizards as pests and not pets. Until2000, very few people owned iguanas — but fea-turing one in a television series changed the wholepicture. The owner of the iguana was portrayed as aweirdo, a societal outcast, a freak with strange haircolor, who, to be honest, was quite funny. And, sud-denly, that was it. Every kid in Greece wanted aniguana. Since the TV-series iguana ate only lettuceand spiders and lived in a 20-gallon tank, it wasapparently easy to keep one. The fact that iguanasare very cheap in Greece has only encouraged peo-ple to acquire one. As a result, according to one ofthe largest pet shops in Athens, iguana sales haverisen 500% in the past few years. On the oppositeside of that coin, however, the mortality rate of thesecreatures is well over 95% — testament to throw-away attitudes toward reptiles and the lack of accu-rate information regarding proper husbandry.

When I was confronted with my iguana’s healthproblems, I quickly reached my wits’ end. The onlysource of help was the Internet. I even sent e-mailsto the Greek Veterinary Committee asking for assis-tance in finding a vet who would work on reptiles.The response was that no Greek vets had any inter-est in reptiles and that reptiles weren’t even consid-ered in university training programs. I also did somelegal research and found out that animal care legis-lation in Greece covers only cats and dogs.

I finally decided to strike out on my own. Aftertwo years of hard work, intensive research, and manysleepless nights, I managed to cure my pet iguana,Eric, who suffered from mites, skin and spike prob-lems, dehydration, advanced tail rot, and feedingproblems. He had carried these problems with himsince the day I saved him from a terrible pet shop,where he had shared a five-gallon tank with anotheriguana. Today he lives in a very large enclosure thatresembles a tropical forest.

I am not one to tell you that all people are incon-siderate and cruel. I believe that proper educationalefforts regarding reptilian pets will eventually incurdramatic improvements. In the interim, I just hopethat the iguanas in Greece remain mute…

Photograph by Andy Gogakis.

Green Iguanas (Iguana iguana) are inap-propriate pets. Like monkeys, raccoons,and skunks, they are cute and tractableas juveniles but become difficult to man-

age as they grow. Most captives suffer one of twofates. Either their needs are poorly met and theydie at a young age, or they grow into large, active,aggressive adults for which few keepers can pro-vide. Reptile adoption and rescue agencies areoverwhelmed with unwanted iguanas. Successfuliguana owners, those experienced in iguana careand behavior, are among the first to suggest thatthis species is a poor choice for all but the mostdedicated keepers.

In choosing a pet, people select reptiles in gen-eral, or iguanas specifically, for a variety of reasons.A small group of keepers has a strong, sincereinterest in herpetology and iguanas in particular.These people make the best keepers, and arealways reading, researching, and trying to improvetheir knowledge and level of care. A bigger groupof keepers uses the reptile to satisfy the basichuman need to be unique and stand out: “Look atme, I have a weird pet.” Many exotic pets are cho-sen for this reason, and these owners often takeshortcuts in providing care because the animalitself is not as important as having it. Still otherschoose a reptile because they are non-allergenic,low-maintenance pets that can be left unattendedfor days at a time, and convenience outweighsdedication. The final group of keepers incorporatesthe impulse buyers who see an interesting, inex-pensive lizard in the pet store and buy it with littleregard for its captive requirements. These people

succumb to what Dr. Doug Mader calls theiguana’s high “cool” factor.

Whatever the reason a reptile is chosen as apet, iguanas are one of the more popular reptilesbecause they are inexpensive and readily available.Moreover, they are vegetarian and, in this age ofanimal rights, many owners prefer not to dealwith insect or rodent prey. The down side, ofcourse, is that vegetarian diets are much more dif-ficult to balance than are insectivorous or carniv-orous diets.

Like Pot-bellied Pigs, hedgehogs, and importedadult Ball Pythons before them, the Green Iguanafad is on the down slope of its bell-shaped curve ofpopularity when compared to the 1990s. The word


1 This feature was adapted from an article of the same titlepresented as part of the Bayer Exotics Symposium in 2002(Suppl. Compend. Contin. Educ. Pract. Vet. 24:13–22).Portions of that and this manuscript are based on Barten,S.L. In Press. Biology: Lizards. In: D.R. Mader (ed.), ReptileMedicine and Surgery. 2nd ed. W.B. Saunders, Inc.,Philadelphia, Pennsylvania. Used with permission of theBayer Corporation and Bayer AG Leverkusen.

A healthy female Green Iguana (Iguana iguana).Photograph by Tom Wiewandt.

Green Iguana Management and Husbandry1

Stephen L. Barten, DVMVernon Hills Animal Hospital, Mundelein, IL 60060

H U S B A N D R Y

is seemingly getting around that these are difficultcaptives. Nevertheless, a core of dedicated keeperswill always be seeking veterinary advice.

One of the biggest problems of keepingiguanas — or any reptile — in captivity is that nostandard of care has been established for them.Indeed, any internet search using the key words“iguanas, pets, and husbandry” (or “care in cap-tivity”) will turn up an astonishing number of per-sonal web pages for individual pet iguanas whichare laden with advice, often conflicting, on captivecare. Recommendations for captive care are almostuniversally based on anecdotal or personal experi-ence with a few specimens rather than scientificresearch. Instead, captive care should be based onthe biology and natural history of iguanas in thewild. The more their conditions mirror what theyevolved to utilize in nature, the healthier captiveiguanas will be.

Natural HistoryFew reptiles have been studied as extensively as

have Green Iguanas. This very brief summary oftheir biology is an overview meant to illustrateapplications to captive management. GreenIguanas inhabit the New World tropics and sub-tropics from northern Mexico to Paraguay andsoutheastern Brazil, along with many Caribbeanislands. Iguanas are diurnal and arboreal, prefer-ring tree tops along rivers, lakes, and mangroveswamps. Trees provide an abundance of sun andshade for thermoregulation and basking, as well asfood and sleeping perches. Iguanas sporadicallydescend to move to other trees, avoid threats ornest. An iguana may stay in one tree for anywherefrom one day to several weeks. Iguanas also utilizemore open, arid habitats if sufficient foodresources are available.

The home range of a reptile is that area uti-lized for acquiring or accessing necessary resourcessuch as food, shelter, basking sites, escape routes,mates, and nesting sites. Home ranges are notdefended against conspecifics and ranges of indi-viduals typically overlap. Territory is that subpor-tion of the home range that is defended from con-specifics or other species, usually because itcontains a critical resource. For iguanas living intrees, food is abundant and the main defendableresource is reproductive females. The measure-ment of home ranges for arboreal species is diffi-cult because it is three-dimensional and containsgaps of unusable areas. Nevertheless, one study

reported mean home ranges for iguanas observedat least three times over a minimum of twomonths. Large males occupied 800 m2, mediumand small males covered 2,200 m2, and femalesranged over 2,450 m2. Another study showedmean daily movement totals of 111 m for maleand 135 m for female iguanas. Flight distances ofiguanas in trees (the distance at which theapproach of a threat caused the lizard to flee) was50–60 m after basking and 90 m before basking.

Iguanas are one of few totally herbivorouslizards. They are joined by many of the otherNew World Iguaninae, the spiny-tailed agamidUromastyx spp., Sailfin Dragons (Hydrosaurusspp.), Fiji Island Iguanas (Brachylophus spp.), andthe Solomon Island Skink (Corucia zebrata).Suggestions that iguanas undergo an ontogeneticshift from insectivory to herbivory are based onobservations of captives and anecdotal fieldobservations and are incorrect. Iguanas spend90–96% of their time resting and only 1% eating.Daily forage times last only 20–30 min. Iguanas


Tropical rain forest in Costa Rica. Green Iguanas were abun-dant and dozens and dozens of adult lizards were seen.

generally eat the leaves of trees and vines. Analysisof stomach contents from 31 iguanas in Panamarevealed only plant material comprising 26 plantspecies. Twenty-four stomachs contained onlyleaves, four contained leaves and flowers, twoonly fruit, and one only flowers. Iguana teethwork like pinking shears and cut out sections ofleaves, but iguanas do not masticate before swal-lowing. All herbivorous lizards have an enlargedcolon divided into compartments by circular andsemilunar valves composed of infolded mucousmembrane, submucosa, and the internal muscu-laris externa. The number of valves varies byspecies and Green Iguanas usually have 6 (5–7,but only four in populations from the northernLesser Antilles). Their function may be to slowgastrointestinal transit time, increase surface area,or provide habitat for commensal microbe and

nematode populations. Wild herbivorous lizardstypically have huge oxyurid (intestinal round-worms) burdens of up to 15,000 worms perlizard. These are not found in other lizardspecies. The nematodes may serve to mechani-cally mix and break down plant material, produceuseable cellulase, vitamins and fatty acids, or pro-mote healthy populations of fermentativemicrobes in the colon. Nevertheless, dewormedlizards had efficient digestion, so nematodes,although common, may be relatively unimpor-tant. Thirty to 40% of nutritional energy derivesfrom microbial fermentation in the hindgut. Thisprocess requires high temperatures and slow pas-sage times, averaging 6.9 days in wild iguanas inVenezuela. Wild neonate iguanas inoculate them-selves with fermentative bacteria by ingesting thefeces of adult iguanas after hatching.


Iguanas are arboreal andprefer trees along rivers, lakesand mangrove swamps (A).This river was in Costa Rica.The speck on the branch ofthis tree is a large GreenIguana (B). Basking high inthe top of a tree is typicaliguana behavior, and servesas proof that most captiveiguanas are kept in inade-quately small cages.

A

B

Thermal ecology of reptiles is complex. Theterm “Preferred Optimum Temperature Zone” iscommon in the veterinary literature, but ther-moregulation in ectotherms involves much morethan that. The “Preferred Temperature” is thetemperature selected by lizards in a thermal gradi-ent when not distracted by other influences, likeshelter. The “Mean Activity Temperature” is themean temperature of all active lizards. The“Activity Temperature Range” is the range inwhich activity occurs. The “Voluntary Minimumand Maximum” are the lowest and highest tem-peratures tolerated in laboratory conditions, andthese define the endpoints of the ActivityTemperature Range. The “Critical ThermalMinimum and Maximum” are the extreme tem-peratures that result in immobility and death.

Voluntary minimum, maximum, and mean tem-peratures for Iguanidae were reported as 18.0°,46.4°, and 36.7° C (64.4°, 115.5°, and 98° F),respectively. Circadian temperature fluctuations(low at night and high during the day) within theactivity temperature range are very important, andlizards kept at uniform temperatures 24 hours aday fail to thrive.

Iguanas appear to have high requirementsfor ultraviolet light for vitamin D and calciummetabolism, although specific wavelengths,intensities, and photoperiods have not beenquantified. Nonbreeding iguanas in Venezuelabasked for approximately 4 h in the morningand another 2–3 h in the afternoon. Baskingprovides for thermoregulatory as well as ultravi-olet needs.


Adaptations for herbivory inGreen Iguanas. (A) Iguanashave homodont (all the sameshape), pleurodont (frequentlyshed and replaced) teethdesigned for cutting largepieces of leaves, which arethen swallowed relativelywhole with little chewing. Thepoints of the teeth interdigi-tate to cut leaves like pinkingshears. (B) Dorsoventralradiograph of an iguana. Thecolon is silhouetted by airdensity in the lung. Thesemilunar valves that dividethe colon into compartments,which are typical of herbivo-rous lizards, are outlined andmade visible by ingesta.

A

B

Iguanas communicate primarily through visualsignals. Dominant males exhibit physical charac-teristics that emphasize their size, such as largeheads, opercular scales, crests, spines, and dewlaps,and sometimes orange skin coloration. Likewise,head bobs, pushups, throat expansions, anddewlap erection are used to convey threat. Threatsmay escalate to lunging, biting, and tail slapping,although, in the wild, displaying males tend to bewell spaced so that displays outnumber actualfights. Chemical and tactile signals are less impor-tant; however, femoral pores are well developed inmales and produce secretions that provide bothchemical and visual cues. The femoral pore secre-tions of Desert Iguanas (Dipsosaurus dorsalis)reflect UV light in wavelengths that are visible tothe lizards but not to humans.

Breeding is seasonal and associated with the dryseason. Males display on perches and defend terri-tories from November through January, becomingvery aggressive toward intruding males. This corre-sponds to a seasonal testicular recrudescence, dur-ing which the testicles undergo marked enlarge-

ment and testosterone production peaks. Breedingbehavior is characterized by dominant male hierar-chies utilizing small mating territories, intense com-petition between males, and female mate selectiondetermined by male fitness. Females nest 3–7 weeksafter breeding, produce clutches ranging from14–76 eggs (average 35–43), and eggs hatch after10–14 weeks of incubation at 28–32° C. Iguanasoften nest communally due to limited numbers ofavailable sites, excavating nest sites at the bottom ofburrows 1–2 m long and 0.25–0.5 m deep. Femalesguard nests from other females.

Nonbreeding iguanas are more tolerant of thepresence of other iguanas and do not defend terri-tories. Low-intensity antagonistic interactionsoccurred when two iguanas passed on a branchbut ceased after they separated. Nonbreedingfemales occupy prime basking and sleeping perchesand chase away new females.

HusbandryThe conditions iguanas require and utilize in

the wild obviously cannot be provided in captivity.


A very large, male, sedated Green Iguana. Size and dominance are communicated through visual cues. Note the large head,large opercular scale on the jowl, large dewlap, and tall dorsal spines. This iguana was caught as a feral animal in Florida,where it was thriving outdoors. The right front foot and forearm are swollen as a result of a bite wound from anotheriguana. Several iguanas including territorial males were housed together due to lack of space at an animal dealer’s facilities.

No iguana husbandry can be described as“proper,” and captive conditions always have roomfor improvement. Captive iguanas tolerate less thanideal conditions, nevertheless keepers must beaware of iguana natural history and make everyeffort to provide for their needs. These needsinclude large, three-dimensional home ranges, focalheat sources approaching 36.7° C (98° F), strongUV sources, a balanced vegetarian diet, and avoid-ance of the various levels of aggressive and antago-nistic behavior between individuals. Every captiveiguana is under some degree of chronic stress justfrom being in captivity. Conditions that are well-tolerated by one lizard may cause serious problemsin another, and keepers must be flexible in theirtechniques according to their results. Captive man-agement should be investigated and improved forany iguana presented to a veterinarian for any rea-son, without exception.

Iguana husbandry has been the subject ofinnumerable books and magazine articles. To coverthe topic in depth here would be to reinvent thewheel, and such a complex subject cannot be dis-cussed in detail in this limited space. Veterinariansand owners alike should be thoroughly familiarwith one or more of the three best books on iguanahusbandry: Kaplan’s Iguanas for Dummies,Hatfield’s Green Iguana: The Ultimate Owner’sManual, and Rosenthal’s The Iguana: An Owner’sGuide to a Happy Healthy Pet. Melissa Kaplan isconsidered a leading authority on captive iguanamanagement and, in addition to her excellentbook, she maintains the Melissa Kaplan’s HerpCare Collection web site at www.anapsid.org. Thisis one of the finest web sites on herp care becauseit is comprehensive, current, accurate, well-refer-enced, and frequently updated.

Two main schools dominate captive reptilehusbandry. Traditionally, bare cages with newspa-per substrate and a single branch and water bowlwere recommended and popular. Ease of mainte-nance was achieved at the cost of stimulation andenrichment for the iguana. Lately, complex, natu-ralistic vivaria have become fashionable. Such cagesare aesthetically pleasing, but also labor-intensive tomaintain, and few but the most dedicated andexperienced hobbyists do an adequate job of sus-taining hygiene in complex cages. If a keeper can-not properly maintain a complex vivarium, then asimpler setup would be a better choice. Likewise,ingestion of substrate is common when gravel orbark is used, especially if the diet is unbalanced or

inadequate in amount. In spite of the potentialproblems, cages should be enriched to reduce stressand allow normal behaviors among inhabitants.

Caging.—Iguanas are arboreal lizards thatrequire huge cages to accommodate their activebehavior, and most keepers provide cages that aretoo small. One expert recommends a cage lengthequal 1.5–2 times the total length of the lizardhoused within, and a cage width at least half thatdistance. Another expert suggests even morespace, 0.4 m3 cage space per 0.1 m total length forarboreal lizards. These are suggestions only andcome nowhere near providing the space that wildiguanas utilize, with home ranges measuring over2,000 m2 (a square measuring 146 ft per side) anddaily movements exceeding 100 m (328 ft). Withthat in mind, iguanas should be provided thebiggest possible cages with the goal for adultlizards of at least 10 x 3 by 6 ft high, although aroom-sized enclosure would be better. Anythingsmaller would be the equivalent of a human livingin a telephone booth: possible, but hardly humane.Aquaria sold for juvenile iguanas will be outgrownin a few months, and the need for custom cagesshould be anticipated from the beginning.Outdoor aviary-style cages with shelters from thesun and inclement weather are strongly recom-mended in warm climates or during the summermonths.

Cage sides should be smooth to prevent ros-tral abrasions. Metal screening should be used withcaution, since it doesn’t retain heat and can resultin foot and rostral trauma. Plastic mesh, polyeth-ylene hardware cloth, and plastic-coated wire meshare less abrasive. Cages made of wood must besealed with polyurethane, marine epoxy paint, or asimilar waterproofing agent, and joints should becaulked to allow cleaning and disinfection.Ventilation is crucial, as ample air exchange is nec-essary to prevent the harmful buildup of bacteriaand fungi.

Lizards allowed to roam free in the house maysuffer suboptimal temperatures from the lack of aheat source or exposure to cold outside walls andwindows or drafty floors. Trauma is common infree-roaming iguanas that may be trampled, closedin doors, fall from high shelves or curtains, or beattacked by dogs and cats. Uncaged iguanas com-monly escape.

Arboreal species require vertical space andclimbing branches. Dry climbing branches approx-imately the same diameter as the lizard’s body


should be placed diagonally in the cage andanchored to prevent toppling. Live, non-toxicplants that lack spines and slippery surfaces and arebig enough to bear the weight of the lizard arerecommended. Dracaena and Ficus trees withtrunks as thick as the lizard’s body work well foriguanas. These act as cage furniture, add humidity,shelter, and visual enhancement. They should bepotted to facilitate cleaning. Silk plants may becoated with toxic, water-soluble stiffeners andshould not be used.

Substrate.—Substrate can be flat newspaper,indoor/outdoor carpet, orchid or so-called “rep-tile” bark chips, alfalfa pellets, cyprus mulch, orcommercial animal bedding made from recycledpaper or wood pulp. Newspaper is inexpensive,clean, and easy to use, but not aesthetically pleas-ing. Carpet is labor-intensive, requiring washing.Alfalfa pellets are digestible if ingested and looknice, but are dusty and foul smelling when they getwet. Orchid or “reptile” bark products made fromfir may be used, but never redwood or cedar. Ifbark chips are excessively dusty, they should berinsed and dried before use. Coarse-grade bark canirritate the feet of lizards that dig repeatedly andfine-grade bark can cause fatal gastrointestinalimpaction if swallowed. With the current popular-ity of naturalistic vivaria, many keepers feel theadvantages of bark outweigh these risks. A shallowfeeding dish can be used to minimize the risk ofaccidental substrate ingestion, but the bark shouldbe removed if a keeper sees the lizard eat some or

finds it in droppings. Recycled paper animal bed-ding currently is a popular substrate to use becauseit is more absorbent and less dusty than alfalfa pel-lets; it can be changed less frequently and it ismore or less digestible if swallowed.

Cedar shavings contain aromatic resins thatmay be toxic to reptiles. Other substrates to avoidinclude gravel, sand, crushed corn cob, clay kittylitter, and miscellaneous wood shavings.

Thermoregulation.—Reptiles are ectother-mic and require supplemental heat in captivity.Temperatures within the Activity TemperatureRange are necessary to optimize metabolicprocesses including digestion, growth, healing,reproduction, and immune system function. TheMean Activity Temperature (Tb, body tempera-ture) for Iguanidae is reportedly 36.7° C (98° F);consequently, a focal hot spot reaching this levelmust be provided. Iguanas also are heliothermic(gain heat by basking) and not thigmothermic(gain heat by conduction from lying on warmrocks), thus overhead heat sources are preferred tosubstrate heaters. So-called hot rocks are com-monly sold by pet stores for use with pet reptiles,but are inappropriate for this species. Substrateheaters under the tank may be used to providebackground heat in cold climates, but not primarybasking heat.

Reptiles in the wild control their core bodytemperature to within a few degrees of their meanactivity temperature by thermoregulation — theymove all or parts of their bodies into or out of


A Bahamian GroundIguana (Cyclura cychlurafigginisi) in a huge outdoorenclosure. Although not aGreen Iguana, theprinciples are the same.About one eighth of thecage is visible here. It islocated under a tree,providing both sun andshade. Note the rampbehind the lizard whichleads to a heated enclo-sure to provide shelter oncool nights. Note, too, thatthe concrete walls areburied in the ground toprevent the lizards fromburrowing underneaththem. Photograph byJuliann Sweet.

direct sunlight. Keepers should create a thermallycomplex environment for captive reptiles to allowthem to adjust their body temperature behav-iorally as they would in the wild. A thermal gradi-ent on both a horizontal and vertical axis is ideal.This can be achieved by providing a focal hot spoton one side of the cage, covering less than 25% ofthe cage, using overhead lamps with reflectors,infrared ceramic heating elements, or radiant heatpanels. These must be secured to prevent themfrom being tipped over or burning the lizard.Heat sources should be attached to thermostats toprevent accidental overheating, and a number ofcommercial models are available specifically foruse with captive reptile enclosures. Fire safety pre-cautions and smoke alarms should be used.However, maintaining the entire cage at a uni-form temperature would be unnatural. Diurnaltemperature fluctuations between day and nightoccur in the wild, so heat lamps should not be lefton 24 h/day. Daily fluctuations in temperatureseem to be important for lizards. Nighttime tem-peratures can approach the voluntary minimumtemperature for iguanas (18.0°C, 64.4°F), butshould not reach it to avoid stress and immuno-suppression. Nighttime lows around 22°C (72°F)are well-tolerated as long as adequate daytimehighs are provided.

The temperatures at both the hottest andcoldest parts of the enclosure must be measureddaily. Digital thermometer-hygrometers are useful.Likewise, infrared thermometers that instantlymeasure the surface temperature of objects from adistance are highly recommended. Both are avail-able from electronics stores and reptile supply deal-ers. Adhesive aquarium thermometers stuck to theside of the cage are not recommended, becausethe temperature of the basking site where the rep-tile rests should be measured rather than the tem-perature on the side of the cage.

Osmoregulation.—Tap water usually is ade-quate, but bottled water might be used where thetap water quality is in question. Aging the water ordechlorination is not necessary. Pseudomonas spp.bacteria grow rapidly in water bowls, so bowlsshould be changed and disinfected or washed inhot soapy water every day.

Humidity is an important but often over-looked factor. In general, iguanas require morehumidity than is typically present in our homes.From a practical standpoint, maintaining humiditylevels of 50% is almost impossible, and such levels

result in blooms of mildew. Good ventilation isessential to prevent the rapid growth of bacteriaand mold in the cage when humidity is added.Humidity may be increased by using water bowlswith large surface areas to increase evaporation,frequent spraying of the cage, or the use of humid-ifiers. Different humidifier models produce hot orcold mist. The former must be kept far enoughfrom the lizard to prevent burns. Machines keptwithin the enclosure must be secured to preventiguanas from tipping them over.

Ultraviolet Requirements.—Ultravioletwavelengths (UV) are important for vitamin Dsynthesis and calcium metabolism in diurnal lizardsthat do not eat vertebrate prey. UV-A (nearwave,320–400 nm) produces beneficial behavioral andpsychologic effects, but does not activate vitaminD precursors in the skin. UV-B (middlewave,290–320 nm) is necessary for vitamin D activa-tion. Reptiles benefit from both UV-A and UV-Blight. Nevertheless, scientific studies into the spe-cific requirement for UV light in captive lizards arelacking, and specific requirements for UV wave-length, intensity, and length of exposure are largelyunknown. Iguanas are known to bask for manyhours every day in the potent tropical sun, receiv-ing levels of UV radiation that are difficult toduplicate in captivity.

The sun is a more effective UV source than anybulb, but certain precautions must be taken beforeexposing captive lizards to direct sunlight. First,window glass filters out UV rays, thus sunlightthrough a window is of no benefit. A reptile in aglass cage should never be placed in direct sunlightor overheating and death may occur. Reptilesshould be in a screen or mesh cage to allow sun-light to enter but, at the same time, prevent theescape of the lizard. Part of this enclosure must beshaded with an overhang or plants to allow the ani-mal to get out of the sun. Iguanas basking in thesun should be kept in an enclosure and not hand-held, even with a leash, because direct sunlight canresult in temporary changes in personality, and nor-mally tame lizards can become agitated and veryaggressive. These changes reverse readily when thelizard is brought back inside. Lizards basking insunlight should be monitored to prevent overheat-ing, exposure to predators, or theft, or any otherproblem that might arise. Basking outside shouldnot be allowed if the ambient temperature is exces-sively high. Even 15–30 min of direct sunlight aweek can be quite beneficial.


A number of artificial UV-B light sources forreptiles are commercially available. Obviously abulb producing 5.0% of its emitted light as UV-Bis more efficient than one producing 2.0% UV-B.Moreover, a 48-inch tube produces more lightthan an 18-inch tube, and two tubes producetwice as much light as a single tube. Traditionally,fluorescent tubes have been considered better UV-B sources than incandescent bulbs, but new prod-ucts are available that claim to provide UV-B andheat in a single incandescent bulb. New UV lightsources are becoming available on a regular basis,and each should be evaluated based on the wave-lengths of UV produced.

Caution should be taken to avoid human expo-sure or eye contact with the UV rays, as these havebeen associated with skin cancer and cataract for-mation. Artificial UV light sources should mimicnatural photoperiods and be turned off at night.

Artificial light sources cannot replace naturalsunlight, and those reptiles with access to the sunin outdoor enclosures, even on a screen porch orpatio, invariably have better growth, health, behav-ior, reproduction, and longevity than those keptindoors.

Visual Security.—Visual security is beneficial,especially for nervous specimens. A shelter or retreatshould be provided for all cage inhabitants. Hidingplaces can be made from a cardboard box, terracotta pottery, plastic flower pots, cardboard tubes,sheets of cork bark, or driftwood. Arboreal iguanas

also should be provided with real or artificial plantsin which to hide. Some iguanas eat poorly andbecome stressed if they lack visual security.

Disinfection.—Cages and food and waterbowls must be cleaned frequently. Three-percentsodium hypochlorite solution is an effective andeconomical disinfectant. The cage and its furnituremust be rinsed thoroughly before returning a lizardto the cage. Keepers must wash their hands thor-oughly after cleaning each cage and not transferwater bowls, uneaten food, or climbing branchesbetween cages without disinfecting them first.

Quarantine.—Reptiles new to a collectionmust be kept in a separate area from the main col-lection for a minimum of 3 months. New arrivalsshould have physical examinations, body weightsrecorded, fecal examinations, parasite treatment,and be monitored for appetite, normal behavior,and symptoms of illness. At the very least, theowner should inspect new arrivals. The main col-lection should be fed and cleaned first and thequarantined animals second, with no transfer ofanimals, cages, food and water bowls, uneatenfood items, or cage furniture between the two.Keepers must wash their hands and consider cloth-ing changes after working with either collection toprevent the inadvertent transfer of pathogens.Ideally, different keepers would care for the twocollections. The farther apart the two collectionsare physically, the less likely an epizootic will occur.No transfer of air should occur between the two


Two Rhinoceros Iguanas (Cyclura cornuta) in a large outdoor enclosure. The lizard on the right is threatening the other onewith vigorous head bobs. Note the erect posture and orientation directly towards the other lizard. The other iguana soonsubmitted by retreating to the far corner of the cage.

groups. When multiple animals are being quaran-tined, they should enter and leave the quarantinearea as a group.

Communal Housing and Handling.—Petstores often display iguanas for sale in crowdedcommunity tanks, suggesting that these are socialanimals. In the wild they may form loose aggrega-tions if food is abundant, but they also have theopportunity to run away if they are being stressedor threatened by other iguanas. Lizards locked ina cage or room cannot run away. Male lizards aremore territorial than females, and react more vio-lently to other males than to females. Hormonefluctuations, and thus territoriality, are seasonaland are manifested most acutely during the breed-ing season. Iguanas gain little benefit from beinghoused together, but cannot stress or injure eachother if housed separately.

When two or more lizards are kept together,the more aggressive individual may physicallyattack the subordinate one, sometimes inflicting

serious wounds. More often it dominates in moresubtle ways by keeping the subordinate lizard awayfrom food and heat sources. This allows the dom-inant one to digest its food more efficiently, growfaster, and have a more effective immune systemthan the subordinate lizard. The subordinate in apair invariably suffers chronic stress, and thus failsto thrive. Symptoms include slow growth, emaci-ation, poor muscle tone, poor color, lethargy, andsusceptibility to infections and parasites. The solu-tion is to separate the lizards. Reflective surfacesand mirrors should be avoided, as lizards, espe-cially males, will attack their own reflection.Keepers might occasionally observe two lizards ina cage to lie in the same spot and overinterpretthat they have a relationship. However, stress maystill be present.

Two or more iguanas may be kept togetheronly if certain requirements are met. First, theenclosure must be large enough, with 1.5–2 timesthe recommended area for the biggest iguana pro-


Multiple bite wounds on the back of a subordinate male iguana, which also suffered a fractured ulna as the result of anadditional bite. Seventy-eight stitches were needed to close the wounds. The owner had purchased two iguanas thinkingthey were social and in need of companionship. As the lizards grew, they both turned out to be males and began to fight.The owner tried to separate them by confining them in separate (and inadequate) 55-gallon aquaria in the same room. Hecame home one day to find the larger male had broken out of his cage and into the cage of the smaller lizard, pinning himdown and chewing on him until the owner separated them.

vided for each iguana in the cage. Second, separatefeeding, basking, and hiding areas must be pro-vided for each iguana. Spatial complexity, so theiguanas can stay out of sight of each other behindlogs, driftwood, and plants, is crucial. Third, keep-ers must be observant of the iguanas’ behavior. Acage may appear suitable by the book, yet the indi-vidual iguanas may require more space or addi-tional shelters or basking sites. Different iguanashave different personalities and requirements.Finally, the keeper must be aware that two iguanassimply may be incompatible. Just because they arethe same species does not mean that they will getalong. Females may dominate males, and smallerlizards may dominate larger ones, so the largestmale is not always at the top of the social hierarchy.Lizards that are initially compatible may begin tofight months or years later. Keepers getting morethan one iguana should be prepared to provideseparate enclosures if the lizards become incom-patible. Separate enclosures are not always enough,and often cages must be kept in separate rooms.

Food and Feeding.—Wild Green Iguanas arespecialized folivores, eating primarily leaves fromtrees. Captive iguanas are exposed to, and accept, anumber of food items they would never see in thewild. The owner must patiently work with his orher pet iguana and train it to eat a balanced diet.The lizard should never be allowed to choose whatit eats, as taste and palatability do not necessarilyequate to nutritional value.

Suboptimal temperatures and other husbandryconditions prevent adequate food intake anddigestion. Under poor captive conditions the bestdiet in the world will be inadequate.

No captive iguana diet can be accuratelydescribed as “proper.” The exact nutritionalrequirements for Green Iguanas have never beenscientifically determined, and precise nutritionalrequirements for this species are not known. Wildiguanas eat leaves from trees that are not availablein captivity. We can approximate a nutritious diet,but most formulations are based on anecdote,experience, and speculation rather than scientificfeeding trials.

In captivity, herbivorous lizard diets should bebased on a variety of chopped, dark green, leafyvegetables. Greens that contain oxalates, likespinach, or goitrogens, like kale, should be usedsparingly. Fruit should be minimized, not becauseit is toxic but because it dilutes the beneficial nutri-ents of the other ingredients. In one study, adding

one cup of strawberries to one cup of romainereduced the protein and calcium concentrations bytwo-thirds compared to romaine alone. A recom-mended diet including ingredients, amounts,schedules, and vitamin and mineral supplementa-tion is described in the accompanying Table.

All plant material must be washed, chopped (afood processor is recommended), and thoroughlymixed. This will ensure a balanced diet in that allfood items will be eaten, rather than just thefavorites or the most tasty items. Prepare enoughfor 4–7 days, store it in the refrigerator betweenfeedings, and serve it at room temperature orslightly warmer. Offer food after the iguana hashad several hours to bask under its heat source inthe morning, leave it in all day and removeuneaten food in the evening.

Grains such as bread, crackers, pasta, and seedsare recommended in some iguana diet recipes.This food group is low in the nutrients thatiguanas need, especially fiber, protein, and calcium.Grains should be limited to occasional treats ifused at all.

Traditionally, animal protein sources have beenrecommended. However, these lizards are vege-tarians from birth, even though they might occa-sionally accept unnatural foods (e.g., crickets oreven mice) in captivity. Although animal proteinsources often are recommended for iguanas, theirnecessity has not been scientifically documented.Any protein supplements should be plant-based.

Commercial iguana diets are available, butvary in quality and palatability. The advantage ofthese products is that they are easier to use thanpreparing a balanced salad several times a week.The disadvantage is that, in spite of claims that thecommercial diets are complete and balanced, theymay not be. Commercial diets that have high lev-els of animal protein, fat, corn, soy, wheat, grains,goitrogenic vegetables, fruits, or flowers should beavoided. The main ingredient, which is alwaysmentioned first on the ingredient list, should bealfalfa. Nutrient levels on a dry matter (DM) basisshould include plant-based protein > 20%, fiber >15%, and calcium 1.4%. Pelleted or powdered dietscontain only 10% water compared to 85–90% insalads. Consequently, these diets must be moist-ened with water prior to feeding. Frozen diets canbe deficient in thiamine. Commercial iguana dietsmay have a role in iguana nutrition but should belimited to less than half of the total diet until moreis known.



Hatchlings (to 14” in length)

• Feed twice a day or provide continuous availability• Plant matter finely chopped or shredded• 1 small pinch of vitamin/mineral supplements per

feeding. Give vitamins 4–5 days a week and cal-cium 7 days a week.

Juveniles (to 2.5 years of age or to 3 ft in length)

• Feed once a day• Plant matter fine to medium chopped or shredded• 1 small pinch of vitamine/mineral supplements per

feeding. Give vitamins 4–5 days a week and cal-cium 7 days a week.

Adults (over 2.5 years of age or over 3 ft in length)

• Feed daily or every other day (an iguana cannot beoverfed when using the high fiber, vegetarian dietrecommended here)

• Plant matter coarsely chopped• One full pinch of vitamine/mineral supplements per

2 lbs of body weight. Give vitamins 2–3 times perweek and calcium 4–5 times per week (unlessgravid or sick, then 5–6 times a week).

Ingredients1. Calcium-rich leafy greens, 40–45% of the diet or

more with three or more items per feeding: turnipgreens, mustard greens, collards, pesticide-freedandelion greens and flowers, clover, escarole,carrot tops, parsley, nasturtium leaves and flowers,and hibiscus leaves and flowers. Also offer endive,romaine, mint, and cilantro.

Spinach, chard and beet greens have high levelsof oxalates which can tie up calcium, and kale,bok choy, and broccoli leaves have high levels ofgoitrogens. Both groups can be used, but in mod-eration.

Iceberg, Boston, butter, and head lettuces have lit-tle nutritional value compared to dark leafygreens. Romaine is intermediate in value, andshould be used only in combination with the darkleafy green mentioned above.

2. Other vegetables, 40–45% of the diet with a vari-ety weekly: raw green beans, snow and snappeas, squash, sweet potato, okra, bell pepper,mushrooms, and yams. Thawed, frozen mixed

vegetables can be used occasionally. Grated car-rot should be used only occasionally, as it also con-tains high levels of oxalates. Vegetables withlower nutritional values include cucumbers, toma-toes, onions, olives, zucchini, and radishes.

3. Alfalfa is a good source of fiber and protein.Alfalfa is available as minibales or pellets for smallmammals from pet and feed stores. Read pelletingredient labels to make sure alfalfa is the firstingredient listed. Do not use mixes that containseeds and other ingredients. Alfalfa also is avail-able as powder, tablets, or capsules from healthfood stores. Pellets and powder should be soft-ened by soaking them in water prior to feeding.Be sure to use mature leaves and stems ratherthan sprouts. If an iguana refuses to eat alfalfa asoffered, powder or crushed tablets can be addedat low levels to the salad, gradually increasing theamount over several weeks.

4. Fruits should be used only as occasional treats orsupplements. Fruits are low in most nutrientsincluding protein and calcium, and have high lev-els of phosphorus. Fruits dilute the good nutrientsfound in leafy greens and vegetables. The follow-ing may be offered: figs, papaya, melon, apple,peaches, plums, strawberries, banana (with skin),grapes, and kiwi.

5. Vitamin and mineral supplementation is advised.Vitamin and mineral deficiencies are common iniguanas. However, calcium and fat-soluble vita-mins (A, D, E, and K) can be oversupplemented aswell as undersupplemented. To avoid oversupple-mentation, natural sources from a varied diet arethe best choice, with moderate vitamin/mineraluse to balance the diet. To date, no documentedstudies address specific requirements for any lizardspecies.

Many commercial supplements are available forreptiles, but none of these products is required toprove potency or safety. Products vary widely inlevels of ingredients. Look for a ratio of roughly100 parts Vitamin A to 10 parts Vitamin D3 to 1part Vitamin E. Human products with Vitamin D3(rather than D2) may also be used. For minerals,use powdered calcium carbonate (cuttleboneshavings is one source) or calcium gluconate.

Vitamin powder on top of the salad may make itunpalatable. The powder should be mixed in thor-oughly. If you can see the powder, you probablyused too much.

Recommended Diet for Captive Green Iguanas

Green Iguanas, especially hatchlings, in retailoutlets are often anorexic, underweight, and weak.They may weigh less than 10 g and have a sunkenabdomen and a bony pelvic girdle. These lizardsshould be force-fed an appropriate vegetarian dietsuch as a commercial tube feed mixture for rabbitsor a gruel of rabbit pellets, as opposed to a liquiddiet for carnivorous dogs and cats, at 1–3% of theirbody weight every two days. At the same time, thejuvenile lizards should be offered a finely choppeddiet, as described in the accompanying Table, untilthey are eating on their own.

ReferencesAlberts, A.C. 1989. Ultraviolet visual sensitivity in Desert Iguanas: impli-

cations for pheromone detection. Anim. Behav. 38:129–137.

Barnett, S.L. 1997. Think “up”: Meeting the needs of arboreallizards, pp. 41–56. In: M.W. Frahm (ed.), Proceedings of theAssociation of Reptilian and Amphibian Veterinarians. ARAV,Houston, Texas.

Barten, S.L. 1993. The medical care of iguanas and other commonpet lizards. Vet. Clin. N. Amer. Sm. Anim. Pract. 23:1213–1249.

Boyer, T.H. 1991. Green Iguana care. Bull. Assoc. Rept. Amphib. Vet.1:12–14.

Boyer, T.H. 1991. Common problems and treatment of the GreenIguana, Iguana iguana. Bull. Assoc. Rept. Amphib. Vet. 1:8–11.

de Vosjoli, P. 1992. The Green Iguana Manual. Advanced VivariumSystems, Lakeside, California.

de Vosjoli, P. 1999. Designing environments for captive amphibiansand reptiles. Vet. Clin. N. Amer. Exotic Anim. Pract. 2:43–68.

Distel, H. and J. Veazey. 1982. The behavioral inventory of the GreenIguana, Iguana iguana, pp. 252–270. In: G.M. Burghardt andA.S. Rand (eds.), Iguanas of the World: Their Behavior, Ecology,and Conservation. Noyes Publications, Park Ridge, New Jersey.

Divers, S.J. 1999. Clinical evaluation of reptiles. Vet. Clin. N. Amer.Exotic Anim. Pract. 2:291–331.

Donoghue, S. 1996. Nutrition of the Green Iguana (Iguana iguana),pp. 99–106. In: M.W. Frahm (ed.), Proceedings of theAssociation of Reptilian and Amphibian Veterinarians. ARAV,Tampa, Florida.

Donoghue, S. 2001. Making the most of diet histories: GreenIguanas. Exotic DVM 3(2):36–37.

Dugan, B. 1982. The mating behavior of the Green Iguana, Iguanaiguana, pp. 320–341. In: G.M. Burghardt and A.S. Rand (eds.),Iguanas of the World: Their Behavior, Ecology, andConservation. Noyes Publications, Park Ridge, New Jersey.

Frye, F.L. 1991. Biomedical and Surgical Aspects of Captive ReptileHusbandry. 2nd ed. Krieger Publ. Co., Malabar, Florida.

Gehrmann, W.H. 1994. Spectral characteristics of lamps commonlyused in herpetoculture. Vivarium 5(5):16–21, 29.

Hatfield, J.W. 1996. Green Iguana: The Ultimate Owner’s Manual.Dunthorpe Press, Portland, Oregon.

Iverson, J.B. 1982. Adaptions to herbivory in iguanine lizards, pp.60–76. In: G.M. Burghardt and A.S. Rand (eds.), Iguanas of theWorld: Their Behavior, Ecology, and Conservation. NoyesPublications, Park Ridge, New Jersey.

Jacobson, E.R. 1988. Evaluation of the reptile patient, pp. 1–18. In:E.R. Jacobson and G.V. Kollias (eds.), Contemporary Issues inSmall Animal Practice: Exotic Animals. Churchill Livingstone,New York.

Jarchow, J.L. 1988. Hospital care of the reptile patient, pp. 19–34.In: E.R. Jacobson and G.V. Kollias (eds.), Contemporary Issues inSmall Animal Practice: Exotic Animals. Churchill Livingstone,New York.

Kaplan, M. 2000. Iguanas for Dummies. IDG Books Worldwide, Inc.,Foster City, California.

Rand, S.A., B.A. Dugan, H. Monteza, and D. Vianda. 1990.The diet of a generalized folivore: Iguana iguana in Panama. J. Herpetol. 24:211–214.

Rodda, G.H. 1992. The mating behavior of Iguana iguana. Smithson.Contrib. Zool. (534):1–40.

Rosenthal, K. 1996. The Iguana: An Owner’s Guide to a HappyHealthy Pet. Howell Book House, New York.

Wiewandt, T.A. 1982. Evolution of nesting pattrns in iguaninelizards, pp. 119–149. In: G.M. Burghardt and A.S. Rand (eds.),Iguanas of the World: Their Behavior, Ecology, andConservation. Noyes Publications, Park Ridge, New Jersey.

Zug, G.R., L.J. Vitt, and J.P. Caldwell. 2001. Herpetology: AnIntroductory Biology of Amphibians and Reptiles. 2nd ed.Academic Press, San Diego, California.


An emaciated Green Iguana acquired by the Mid-MichiganReptile Rescue. Photograph by Stephanie Beiser.

A healthy Exuma Islands Iguana (Cyclura cychlura figginsi)enjoys a properly prepared meal. Photograph by Juliann Sweet.

As for so many of us with an interest iniguanas, an early educational experiencesparked Allison Alberts to pursue a careerin science. She grew up in the San

Francisco Bay Area of northern California, anurban center in close proximity to some of themost diverse and beautiful landscapes in theUnited States. When she entered the University ofCalifornia–Berkeley, she was undecided in herstudies, exploring both English and science. Notuntil she enrolled in a two-semester course entitledNatural History of the Vertebrates, which includedonce-a-week field trips, did her enthusiasm for acareer in science solidify. After graduating withhigh honors in biology, she moved to theUniversity of California–San Diego to begin apost-doctoral program. After her first year, sheenrolled in the Tropical Ecology course with theOrganization for Tropical Studies in Costa Rica.This was the first time Allison had traveled to thetropics and the experience was very influential indeveloping her career interests. Allison’s originalthesis topic had been chemical communicationstrategies among Neotropical bats. However, aftera few years (and some crazy adventures inMexico), she realized that bat research in the trop-ics was logistically nightmarish and far too costlyfor a graduate student. She switched her thesis tochemical communication in Desert Iguanas(Dipsosaurus dorsalis), a project that could beaccomplished in the deserts just east and north ofSan Diego. In many ways, Allison is thankful thatshe switched her thesis in mid-stride, as she hasindeed fallen in love with lizard ecology!

As a post-doctoral fellow, Allison expandedupon her graduate work by examining communi-cation in a species closely related to Dipsosaurus,but which experienced radically different habitatparameters. Wanting to return to the tropics, shebegan studying Green Iguana (Iguana iguana)chemical communication. This research was con-ducted partly in the field at Dagmar Werner’s

iguana ranch in Costa Rica, partly in the laboratoryat Texas A&M University in College Station, andculminated at the Zoological Society of SanDiego’s Center for Reproduction of EndangeredSpecies. At CRES, Allison was exposed to abroader scope of research that included conserva-tion as well as academic goals. After becoming anassociate scientist at the San Diego Zoo, she beganstudying the ecology and reproductive biology ofa relatively stable population of Cuban Iguanas(Cyclura nubila nubila) at the U.S. Naval Stationat Guantanamo Bay, Cuba. As a group, theCaribbean iguanas are the most endangered lizards

P R O F I L E142 IGUANA Volume 10, Number 4

Allison Alberts: A Consumate Conservationist

Tandora GrantCenter for Reproduction of Endangered Species, Zoological Society of San Diego

Allison and Cuban Iguana, “Sunny,” at the San Diego Zoo.

on earth, primarily due to habitat alteration andpredation by introduced domestic and feral mam-mals. Many populations consist solely of adultiguanas with virtually no juvenile recruitment. Alarge and pioneering part of the Cuban Iguanaresearch, supported by the National ScienceFoundation, included testing the viability of head-starting as a conservation strategy for depletedpopulations of large lizards. To quickly rebuildsuch a population, determining if hatchlingiguanas could be raised in captivity until theyobtain a size less vulnerable to predators and suc-cessfully persist in the wild was essential.

In 1991, the Jamaican Iguana (Cyclura collei)was rediscovered in a remnant patch of forest nearKingston. A year later, the Conservation BreedingSpecialist Group hosted a ConservationAssessment and Management Plan workshop foriguanids and varanids, which was soon followed bya Population Habitat Viability Assessment work-shop for the Jamaican Iguana. As a participant inthese two workshops, Allison met many key peo-ple concerned with the conservation of Caribbeaniguanas. Among these new colleagues was RickHudson of the Fort Worth Zoo in Texas, withwhom she began incubating the idea of forming aspecialist group for Caribbean iguanas. Togetherthey organized the first informal meeting in Miamiin 1996, which was attended by 25 people

from six countries.Official sanction fromIUCN (The WorldConservation Union)in 1997 formally estab-lished the West IndianIguana SpecialistGroup. Since that firstmeeting, the group hasmet every year to discuss on-goingresearch, developrecovery strategies, andstrengthen collabora-tions. The partnershipsformed have beeninstrumental in theremarkable populationrecovery milestones for Caribbean RockIguanas seen in the lastdecade. Headstartingis now being success-


Young iguana conservationists in training: Allison’s childrenJonathan (age 4) and Connor (age 6). Allison was instru-mental in erecting these iguana-warning signs at the U.S.Naval Station at Guantanamo Bay, Cuba.

Allison with Iguana Specialist Group members, Rick Hudson, Fort Worth Zoo, and MiguelGarcía, Puerto Rico Department of Natural Resources, leads the 2002 Iguana SpecialistGroup meeting in the Dominican Republic.

fully applied to wild populations in Jamaica, GrandCayman (Cyclura lewisi), Mona Island (Cycluracornuta stejnegeri), and Anegada (Cyclurapinguis). Dr. Alberts’ team has also been investi-gating how quickly iguana populations can recoverafter severe habitat disturbance in Cuba and usingtranslocation to restore iguana populations to for-merly inhabited cays in the Turks and CaicosIslands.

These days Allison spends less time in thefield than in the past. As Head of the AppliedConservation Division at the San Diego Zoo,she oversees a staff of seventeen, with projectsthat focus on the reintroduction of ecologicallyimportant species, sustainable use of naturalresources, and Southern California species andhabitat conservation. Conservation of iguanasremains a principal focus for her and many of thedivision’s staff members, but the group also isactively involved in reintroduction programs forthe California Condor, San Clemente IslandLoggerhead Shrike, and Giant ChacoanPeccaries in Paraguay. Additionally, because con-servation nearly always requires modifications ofhuman behavior, the division’s projects inMadagascar and Mexico work with indigenouscommunities to develop butterfly-based pro-grams that provide significant income, while atthe same time promoting habitat preservation

and restoration. Finally, because San Diego islocated in one of the world’s biodiversityhotspots, the division’s research continues tosupport conservation of Southern Californiaecosystems, through a seed banking effort andongoing studies of local birds, mammals, reptiles,and their habitats. Summaries of some of theseprojects can be viewed on the San Diego Zoo’swebsite (http://www.sandiegozoo.org/conser-vation/field_projects_list.html).

Allison is the author of over forty journal arti-cles, two books, ten book chapters, and scores oftechnical reports and popular articles. She hasserved on numerous editorial review boards and isa key contributor to several professional societies.Today, the West Indian Iguana Specialist Grouphas expanded its mandate to become a globalIguana Specialist Group that includes membersconcerned with all iguanids. Allison has beenelected Co-Chair since the group’s inception,which attests to her skills in diplomacy and com-munication, and to her science-based approach toconservation. Outside of work, Allison enjoysspending time with her husband Mike and twosons, Connor and Jonathan, as well as swimming,softball, reading, hiking, gardening, and travel. Sheis distinguished among scientists by her strongconservation ethic and compassion for the animalsshe studies.


Allison and iguana friends (Cyclura cychlura inornata) on the Allen Cays, Bahamas.

Allison Alberts and GlennGerber release Turks andCaicos Iguanas (Cycluracarinata carinata) on BayCay as part of a long-termrestoration program forthe species.

The Galápagos Islands are a world untothemselves. The majority of the plants andanimals there are found nowhere else.Among the animals, the reptiles play a very

important role, ecologically replacing the mam-mals that are absent from the islands, especially theherbivores. Only a few species are native, but eachis (or was only a few decades ago) exceedinglyabundant. Of particular interest are the iguaniansquamates and, of those, two exceptionallyunusual species stand out. These are easily distin-

guished from related iguanas by examining theirdentition, the shape and scalation of their heads,the strength of the head skeleton, and the lack ofa dewlap. Both species agree in general body formand they also demonstrate some behavioral simi-larities; neither of the two is particularly mobileand both are vegetarian, although they consumevery different plants. In fact, one lives on land andthe other is completely dependent upon water.Unique among squamates, the latter, which canaccurately be called a marine animal, feeds exclu-sively on aquatic plants.

The Sea-lizard, as we are wont to call it,Amblyrhynchus cristatus Bell [translator’s note:Thomas Bell was an Englishman who namedmany amphibians and reptiles in the 19th century],is the only representative of its genus. It is a verylarge iguana. Of the total length of 135 cm, 80 cmis tail. Weight can reach 12 kg. The short, broadhead slopes steeply to each side, tapers toward thefront, and the profile arches rapidly and sharply

from the forehead tothe blunt snout. Tobest characterize thebeast, I have taken thefollowing informationfrom Steindachner[Franz Steindachnerwas an Austrian ichthy-ologist and herpetolo-gist associated with theVienna Museum ofNatural History from1860 until his death in1919], who wrote atreatise on the squa-mates of the GalápagosIslands [published in1876]: The entire topof the head is coveredin mosaic fashion by

H I S T O R I C A L P E R S P E C T I V E S145IGUANADecember 2003

Iguanas of the Galápagos Islands1

Franz Werner, with extensive quotations from Charles Darwin

Sea-lizard, Amblyrhynchuscristatus Bell. 1/6 natural size.

1 Excerpted and translated from Franz Werner (1913. DieLurche und Kriechtiere von Alfred Brehm. Zweiter Band:Kriechtiere (Schuppenkriechtiere), pp. 86–92 + table “LizardsV,” no. 3. In O. z. Strassen (ed.), Brehms Tierleben.Allgemeine Kunde des Tierreichs. 4th ed. BibliographischesInstitut, Leipzig and Wien. Translated by R. Powell. Quotesfrom Darwin were not translated from Werner’s text, butinstead were taken directly from C. Darwin (1845. TheVoyage of the Beagle. 2nd ed.). Some excerpts omitted byWerner are included here.

many quadrangular (usually) or six-sided scales ofvarying sizes; the largest are conical or evenpointed and lie primarily toward the front of thehead, whereas the smallest form the supraocularshields. The lateral but relatively highly situated,egg-shaped nares are angled from low in front tohigh in back, and are surrounded by an elevatedleathery rim, which in turn is surrounded by smallscales. Nine to ten five-sided plates form the upperlip and 12–13 four-sided plates make up the lowerlip. An arc-like band of keeled scales extends fromthe region under the eye to the temple, whereasthe underside of the head is covered by smallrounded scales. The egg-shaped tympanum isembedded in a raised border of tubercular scales.The skin of the throat and neck is more or lessloosely attached and forms a distinct gular fold.The body is generally robust, and the dorsal crestis continuous from the neck to the tip of the tail,although indentations mark the transitions fromneck to body and body to tail. The scales of thebody are distinguished by size and location. Dorsalscales are all keeled, lateral scales are tuberculate,whereas the ventral scales are completely smooth.The long tail has a thick base but becomes dis-tinctly compressed laterally toward the tip, inessence forming a paddle or fin. The tail is coveredwith keeled scales, like those on the back, arrangedin distinct rings. The limbs are short and stocky.The third and fourth toes are of equal length and

are longer than theothers. All are con-nected by a small weband equipped withpowerful, sharp, andslightly arched claws.The thick tongue is aswide as the mouth.The long, large teethare serrated andattached to the outerfold of the deeplygrooved jaws. Eachupper jaw bears 22–25teeth, each lower jaw20–24, of which 6–8are similar to the lateralteeth and are on theintermaxilla. The smalland not particularlynumerous teeth on the

pterygoid and sphenoid are easily displaced.Color and pattern vary by age. Young Sea-

lizards have numerous light gray flecks on bothsides of the head, the chin, and on the sides of thebody. These may reduce the black ground color tonet-like reticulum. On the back, alternating dirtygray and black bands of flecks produce a more orless regular pattern of crossbands. The upper andlateral sides of the limbs are either punctuated withsmall gray flecks or larger gray spots. The chin is adark dirty gray, the throat is black, and the belly adirty yellow-brown. The digits, the axilla andgroin, and the distal half of the tail are black. Thedorsal crest is variably yellow or gray with blackbands. Occasional individuals are entirely black.

Sea-lizards are phenomenally abundant on theGalápagos Islands. Darwin found them on all ofthe islands he visited; Steindachner found them onAlbemarle, Charles, James, and Jervis islands, withthose on the latter in particularly large numbersand including some individuals of imposing size;W.E. Cookson [an English explorer] also foundthem on Abingdon Island. Corresponding to theirhabits, these lizards restrict themselves to the rockyshorelines and, according to Darwin’s observa-tions, are not to be found more than 10 pacesfrom the water’s edge.

Darwin noted: “They are occasionally seensome hundred yards from the shore, swimmingabout; and Captain Collnet, in his Voyage, says,


Granular-head, Conolophus subcristatus Gray. 1/5 natural size.

‘They go to sea in herds a-fishing, and sun them-selves on the rocks; and may be called alligators inminiature.’ It must not, however, be supposed thatthey live on fish. When in the water this lizardswims with perfect ease and quickness, by a ser-pentine movement of its body and flattened tail —the legs being motionless and closely collapsed onits sides. A seaman on board sank one, with aheavy weight attached to it, thinking thus to kill itdirectly; but when, an hour afterwards, he drew upthe line, it was quite active. Their limbs and strongclaws are admirably adapted for crawling over therugged and fissured masses of lava, which every-where form the coast. In such situations, a groupof six or seven of these hideous reptiles may often-times be seen on the black rocks, a few feet abovethe surf, basking in the sun with outstretched legs.

“I opened the stomachs of several, and foundthem largely distended with minced sea-weed(Ulæ), which grows in thin foliacious expansions ofa bright green or a dull red colour. I do not recol-lect having observed this sea-weed in any quantityon the tidal rocks; and I have reason to believe itgrows at the bottom of the sea, at some little dis-tance from the coast. If such be the case, the objectof these animals occasionally going out to sea isexplained. The stomach contained nothing but thesea-weed. Mr. Bynoe, however, found a piece of acrab in one; but this might have got in accidentally,in the same manner as I have seen a caterpillar, inthe midst of some lichen, in the paunch of a tor-toise. The intestines were large, as in other herbiv-orous animals. The nature of this lizard’s food, aswell as the structure of its tail and feet, and the factof its having been seen voluntarily swimming outto sea, absolutely prove its aquatic habits; yet thereis in this respect one strange anomaly, namely, thatwhen frightened it will not enter the water. Hence

it is easy to drive these lizards down to any littlepoint overhanging the sea, where they will soonerallow a person to catch hold of their tails than jumpin the water. They do not seem to have any notionof biting; but when much frightened they squirt adrop of fluid from each nostril. I threw one severaltimes as far as I could, into a deep pool left by theretiring tide; but it invariably returned in a directline to the spot where I stood. It swam near thebottom, with a very graceful and rapid movement,and occasionally aided itself over the unevenground with its feet. As soon as it arrived near theedge, but still being under water, it tried to concealitself in the tufts of sea-weed, or it entered somecrevice. As soon as it thought the danger was past,it crawled out on the dry rocks, and shuffled awayas quickly as it could. I several times caught thissame lizard, by driving it down to a point, andthough possessed of such perfect powers of divingand swimming, nothing would induce it to enterthe water; and as often as I threw it in, it returnedin the manner above described. Perhaps this singu-lar piece of apparent stupidity may be accounted forby the circumstance, that this reptile has no enemywhatsoever on shore, whereas at sea it must oftenfall prey to the numerous sharks. Hence, probably,urged by a fixed and hereditary instinct that theshore is its place of safety, whatever the emergencymay be, it there takes refuge.” Darwin was unableto address reproduction in these animals.

Steindachner visited the Galápagos Islands in1872 and, like Dampier and Darwin before him,saw thousands of Sea-lizards. “When my fellowtraveler, Pitkins, saw a large number of thesehideous animals, he ran into the midst of thedensely packed mass. When I visited the same siteshortly thereafter and again after about an hour, itwas completely void of lizards. They had all fled

into the sea and proba-bly had sought outanother, more distantrefuge. My experience,also on James andJervis islands, indicatedthat the sea-lizards,although sluggish andawkward in theirmovements and easilycaptured without resis-tance, do these daysseek the sea to escape


Granular-head, Conolophus subcristatus Gray. 1/8 natural size. Photograph by W.P. Dando,F.Z.S. – London.

potential threats when they notice enemies in thevicinity — instead of, as earlier, returning stub-bornly to the same site on shore. On calm days,one frequently encounters these lizards long dis-tances from shore swimming and diving with easeand surprising speed. Their movements in waterresemble those of a snake. Only the head is emer-gent while swimming, and the limbs are adpressed.On Jervis Island, I found them only in the imme-diate vicinity of the sea, usually in herd-like massesof 100–150 packed into small spaces on the roughand rugged lava. On James Island, I encounteredonly a few individuals considerably above the shorealong the edges of small, overgrown cavities in therocks that might serve as nesting sites. The stom-ach and intestine, as Darwin already mentioned,are without exception stuffed with foliacious greenor dull-red algae.”

The second lizard of theGalápagos Islands, which we will callthe Granular-head, differs distinctlyfrom the Sea-lizard in overall statureand in the absence of pterygoid teethin adults. Overall, these are evenmore plump and ponderous.Restricted to dry land, they lack web-bing between the short toes that ter-minate the stout limbs. The tail also isshorter and only slightly compressed,oval in cross-section and almost with-out a crest. In contrast, the neck isconsiderably longer and bears longi-tudinal folds of skin on its underside.The head also is more elongate, con-sequently less distinctly arched in pro-file and sloping less steeply to thesides. For all of these reasons,Steindachner agreed with thoseresearchers who considered theGranular-head, Conolophus subcrista-tus Gray [John Edward Gray was a19th century English naturalist and iswidely regarded as the founder of theherpetological collections at theBritish Museum], to be a representa-tive of a unique genus (ConolophusFitz. [“Fitz. refers to LeopoldFitzinger, a prolific Austrian zoologistwho wrote Neue Classification derReptilien in 1826 and SystemaReptilium in 1843]).

In terms of color, the Granular-head differsconsiderably from the Sea-lizard. The head is amore or less lively yellow, the back near the crest isbrick- or rust-red, and, in rare cases, the bodysports faint, alternating yellowish and reddish-brown crossbands. Down the sides, the reddish-brown color gives way to a dirty, dark brown.Here and there, one may notice dots or smallblack flecks with indistinct edges. The belly is darkyellow with a tinge of reddish-brown. The upperand outer surfaces of the forelimbs are reddish, thehindlimbs are brownish yellow, but the claws andtoes are black. These lizards reach a length of 107cm, of which 54 cm is tail.

Darwin observed Granular-heads in the cen-tral islands of the Galápagos Archipelago,Albemarle, James, Barrington, and Indefatigable,where they occupy both the higher, moister areas


Illustration by John Binns.

and the lower, infertile regions, where they actu-ally are more common. Darwin noted: “I cannotgive a more forcible proof of their numbers, thanby stating that when we were left at James Island,we could not for some time find a spot free fromtheir burrows on which to pitch our single tent.Like their brothers the sea-kind, they are ugly ani-mals, of a yellowish orange beneath, and of abrownish red colour above: from their low facialangle they have a singularly stupid appearance.They are, perhaps, of a rather less size than themarine species; but several of them weighedbetween ten and fifteen pounds. In their move-ments they are lazy and half torpid. When notfrightened, they slowly crawl along with their tailsand bellies dragging on the ground. They oftenstop, and doze for a minute or two, with closedeyes and hind legs spread out on the parched soil.

They inhabit burrows, which they sometimesmake between fragments of lava, but more gener-ally on level patches of the soft sandstone-like tuff.The holes do not appear to be very deep, and theyenter the ground at a small angle; so that whenwalking over these lizard-warrens, the soil is con-stantly giving way, much to the annoyance of thetired walker. This animal, when making its burrow,works alternately the opposite sides of its body. Onefront leg for a short time scratches up the soil, andthrows it towards the hind foot, which is well placedso as to heave it beyond the mouth of the hole.That side of the body being tired, the other takes upthe task, and so on alternately. I watched one for along time, till half its body was buried; I thenwalked up and pulled it by the tail; at this it wasgreatly astonished, and soon shuffled up to see whatwas the matter; and then stared me in the face, asmuch as to say, ‘What made you pull my tail?’

“They feed by day, and do not wander farfrom their burrows; if frightened, they rush tothem with a most awkward gait. Except when run-ning down hill, they cannot move very fast, appar-ently from the lateral position of their legs. Theyare not at all timorous: when attentively watchingany one, they curl their tails, and, raising them-selves on their front legs, nod their heads vertically,with a quick movement, and try to look veryfierce: but in reality they are not at all so; if one juststamps on the ground, down go their tails, and offthey shuffle as quickly as they can. I have fre-quently observed small fly-eating lizards, whenwatching anything, nod their heads in precisely the

same manner; but I do not at all know for whatpurpose. If this Amblyrhynchus [in Darwin’s day,both Galápagos iguanas were placed in the genusAmblyrhynchus] is held and plagued with a stick, itwill bite it very severely; but I caught many by thetail, and they never tried to bite me. If two areplaced on the ground and held together, they willfight, and bite each other till blood is drawn.

“The individuals, and they are the greater num-ber, which inhabit the lower country, can scarcelytaste a drop of water throughout the year; but theyconsume much of the succulent cactus, thebranches of which are occasionally broken off by thewind. I several times threw a piece to two or threeof them when together; and it was amusing enoughto see them trying to seize and carry it away in theirmouths, like so many hungry dogs with a bone.They eat very deliberately, but do not chew theirfood. The little birds are aware how harmless thesecreatures are: I have seen one of the thick-billedfinches picking at one end of a piece of cactus(which is much relished by all the animals of thelower region), whilst a lizard was eating at the otherend; and afterwards the little bird with the utmostindifference hopped on the back of the reptile.

I opened the stomach of several, and foundthem full of vegetable fibres and leaves of differenttrees, especially of an acacia. In the upper regionthey live chiefly on the acid and astringent berriesof the guayavita, under which trees I have seenthese lizards and huge tortoises feeding together.To obtain the acacia-leaves they crawl up the lowstunted trees; and it is not uncommon to see a pairquietly browsing, whilst seated on a branch severalfeet above the ground. These lizards, whencooked, yield a white meat, which is liked by thosewhose stomachs soar above all prejudices.Humboldt [Alexander von Humboldt, a famousGerman naturalist whose explorations of SouthAmerica thrilled Europe and inspired Darwin] hasremarked that in intertropical South America, alllizards which inhabit dry regions are esteemed del-icacies for the table. The inhabitants state thatthose which inhabit the upper damp parts drinkwater, but that the others do not, like the tortoises,travel up for it from the lower sterile country. Atthe time of our visit, the females had within theirbodies numerous large, elongated eggs, whichthey lay in their burrows: the inhabitants seekthem for food.”



Franz Werner was born and raised in Vienna. Atthe age of six, his father presented him with a littleglass terrarium in which a Green Treefrog (Hylaarborea) was supposed to forecast the weather byselecting perches on a miniature step ladder pro-vided for that purpose. A common European SandLizard (Lacerta agilis) soon joined the treefrog — anda lifelong interest in herpetology was established.

Werner studied zoology at the University ofVienna, receiving his doctorate in 1890. He studiedbriefly in Leipzig before moving back to Vienna in1895 to accept an appointment at the ImperialZoological Institute at the university. Herose to full professor in 1919, retired in1933, and died in 1939.

Despite an inability to work with theherpetological collection at the Natur-historiches Museum in Vienna, due tothe personal animosity of the director,Franz Steindachner, who may have per-ceived Werner as a competitor, Wernerused material from other European

museums and those in his personal collection topublish over 550 titles, most in herpetology. Hedescribed 24 genera and over 400 species and sub-species of amphibians and reptiles. Although heoccasionally erred in describing as new well-knownspecies based on specimens with poor or erroneouslocality data, most of his work was quite competent.

Werner’s major works included faunal surveysof Austria-Hungary (1897), the Bismarck Archi-pelago east of New Guinea (1900), and Greece(1938). Taxonomic monographs included one onchameleons (1902), a three-part series on colubrid

snakes (1923, 1924,1929), several issuesin Das Tierreich series,and the two herpeto-logical volumes in thefourth edition ofAlfred Brehm’s “Tier-leben” series (1912–1913), from whichthe current and recentexcerpts were taken.He also wrote the sec-tion on amphibiansfor the Handbuch derZoologie (1930) and,with Rodolpho Kraus,the standard work onvenoms and veno-mous snakes (1931).

Unlike many scien-tists, Werner was notaverse to popular orsemi-popular writing.

His efforts along those lines, particularly a little vol-ume entitled “Amphibien und Reptilien” (1910), didmuch to develop an interest in herpetology amongGerman-speaking people, to encourage amateurs,and to stimulate and inspire young zoologists.

Sources:Adler, K. 1989. Herpetologists of the past, pp. 5–141. In:

K. Adler (ed.), Contributions to the History of Herpetology.Society for the Study of Amphibians and Reptiles,Contributions to Herpetology, Number 5. Ithaca, New York.

Mosauer, W. 1940. Franz Werner (1867–1939). Herpetologica1:178–183.

B I O G R A P H I C A L S K E T C H : Franz Werner (1867–1939)

Franz Werner with a Boaconstrictor (photographcourtesy of Kraig Adler).

Franz Werner at Djebel Zalagh, near Fes, Morocco in1928 (photograph courtesty of Kraig Adler).

B O O K R E V I E W151IGUANADecember 2003

Islands and the Sea: Essays on HerpetologicalExploration in the West Indies. Robert W.Henderson and Robert Powell (editors). 2003.Society for the Study of Amphibians andReptiles (SSAR), Ithaca, New York. 312 p.,316 photographs, 14 maps, indices.Clothbound, $48. Available from: BreckBartholomew, SSAR Publications Secretary,P.O. Box 58517, Salt Lake City, Utah84158–0517 ([email protected]).

I will admit to having a few regrets in mycareer, and certainly my decision to decline BobPowell’s invitation to contribute an essay to thisvolume ranks among the highest. For anyone whohas dedicated part of their career to working in theCaribbean, for those with a strong interest in thenatural history and biogeography of islands, or ifyou simply enjoy stories of herpetological explo-ration and discovery, this is must-read material.

The book is well organized, 300 pages dividedinto six sections corresponding to the major islandgroups in the Caribbean: the Greater Antilles(Cuba, Jamaica, Hispaniola, and Puerto Rico), theBahamas, and the Lesser Antilles. Regrettably,some islands received short coverage, with onlyone essay on Puerto Rico and none on the Turks& Caicos. Powell and Henderson’s introductionand historical perspectives set the tone for thebook and provide the reader with a scholarlyoverview of many of the early herpetologists andremarkable personalities that did much of the pio-neering exploration in the West Indies.

Herpetological research in the West Indies isan intriguing pursuit for many reasons, the firstand foremost being a remarkable degree of diver-sity. Recognized as one of the world’s biodiversityhotspots, this is particularly evident with herps. Anarchipelago containing several hundred islands,ranging from huge landmasses to minute specs ofland, the Caribbean is a living laboratory of evolu-tion and speciation. Boasting over 600 species ofreptiles and amphibians and a remarkably high rateof endemism, the Caribbean ranks second only toMesoamerica in terms of reptilian diversity (438species) and has the highest rate of endemism(84%) of any region in the world. Amphibians,though not as diverse, have a comparable rate of

endemism (86%). These impressive figures, com-bined with elevated numbers for vascular plantsand birds, provide ample incentive for urgent con-servation measures in these delicate ecosystems —but much of the Caribbean is under intense pres-sure and, sadly, many of us now devote consider-able time and energy trying to save the last vestigesof species ravaged by the effects of man. I oftenwonder, and I know my colleagues share this sen-timent, what it would have been like to set foot onthese islands 100–200 years ago when they werestill largely pristine.

The essays in this volume cover a broadexpanse of time, dating from the 1950s to the pre-sent. Those early stories of herpetological field-work and discovery (Stan Rand and SixtoIncháustegui in the Dominican Republic, SkipLazell in the Lesser Antilles, Meg Stewart inJamaica, and Orlando Garrido in Cuba) take usback to a simpler time when collecting was lesscomplicated (except for travel) and the habitats lessdamaged. The essays on Cuba, to me, are particu-larly compelling because they offer vignettes into aworld that, due to narrow-minded political agen-

Ed. note: This review by Rick Hudson will also appear in theBulletin of the Chicago Herpetological Society.

das, few of us have the opportunity to experience.Perhaps the best read in this series is AlbertoEstrada’s vivid description of collecting herps whileon an expedition to find a remnant population ofIvory-billed Woodpeckers. This story is bothpoignant and haunting in that we are able toglimpse, through a narrow window in time, thelast sightings of a species before it slipped quietlyinto extinction.

The genus Anolis has undergone a remarkabledegree of speciation in the Caribbean, where itreaches its apex of diversity, providing ampleopportunities for fieldwork and research. Nowhereis this more evident than Richard Glor’s“Rediscovering the Diversity of DominicanAnoles.” Written in a fast-paced narrative, thislively essay recounts the ambitious attempt by himand his colleagues to collect all 40 species ofDominican anoles, a determined mission that lit-erally comes down to the last species on the lastday of their trip. An engaging story, this is aboutas exciting as herpetological reading can get.

Of course, no coverage of the Caribbean her-petofauna would be complete without featuringthe prehistoric-looking Rock Iguanas of the genusCyclura for which the islands are so well known.Undoubtedly the most conspicuous element ofthe region’s reptilian fauna (evidenced by the pho-tograph gracing the dusk jacket), these charismaticlizards have become flagship species for conserva-tion in the West Indies. This book includes chap-ters describing Cuban Iguanas at Guantanamo Bay(Allison Alberts), Andros Iguanas (Chuck Knapp)and Allen’s Cay Iguanas (Jen Valiulis et al.) in theBahamas, Jamaican Iguanas in the Hellshire Hills(Byron Wilson), and Rhinoceros and Ricord’siguanas on Isla Cabritos, Dominican Republic(Sixto Incháustegui). Of particular interest inSixto’s chapter is a rare photo of Michael Carey, awell-known and near legendary (in that he seemedto vanish, dropping out of sight in the 1980s)Cyclura biologist, who published some seminalworks on the genus through the Florida StateMuseum. For those of us obsessed with RockIguanas in the late 1970s and 80s, his was some ofthe most treasured reading material available.

Iguana delicatissima is discussed several timesin the Lesser Antillean section, nowhere morevividly than in Michel Brueil’s account, “In theFootsteps of French Naturalists.” He examines the

processes (man-made, most harmful and negative,as well as natural) dating back to European colo-nization that have accounted for some of the per-plexing distribution patterns seen in the FrenchWest Indies, including that of the genus Iguana.His story provides compelling evidence of justhow rapidly species’ distributions can change overa relatively short period of time, events whichshould cause us great concern given how thisprocess has been accelerated today. This essay alsoprovides cause for optimism in that it demonstratesthe resiliency of many island populations (in thiscase a population of I. delicatissima reduced byhalf — from an estimated 10,000 to 5,000 — bya severe drought) and their ability to persist andrebound from horrendous natural disasters. Thischapter also reinforces the reality that the primarythreat to biodiversity in the region is introducedexotics.

My complaints on this book are few and onlyone merits mention. Photo credits are conspicu-ously absent from most of the book. They are pro-vided inconsistently, some chapters have them butmost do not. Maybe this is just a quirk of mine,but I like to know who shot the images. As it turnsout, uncredited photos are by the authors of therespective essays, but nowhere is this explained. Ifound very few grammatical errors, and the edit-ing appears to be thorough, the exceptions beinga disparity in the number of Cuban anoles (59 byGarrido’s count; “about 50” according to GeorgeGorman) and a statement in Hinrich Kaiser’s essaythat Eleutherodactylus amplinympha is Dominica’sonly endemic vertebrate (it is the island’s onlyendemic frog).

All in all, this is a thoroughly enjoyable readand I highly recommend it. If you are already pas-sionate about Caribbean herpetology and workingin the islands, this is required reading. If you havenot experienced the sheer joy and exhilaration ofexploring some of these remarkable destinations,this book should provide the spark that initiatesyour conversion. The allure of these islands is pow-erful, and once experienced, hard to shake off. Butthen who would want to?

Rick HudsonCo-chair, IUCN Iguana Specialist Group

Program Officer, International Iguana FoundationConservation Biologist, Fort Worth Zoo

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I G U A N A N E W S B R I E F S153IGUANADecember 2003

New Cyclura Residence atthe Bristol Zoo

Although Green Iguanas remainpopular pets, interest in iguanas inEngland is minimal, and opportunitiesto see them are virtually non-existent.The genus Cyclura is represented solelyby Cyclura cornuta, the HispaniolanRhinoceros Iguana, and British zoo pol-icy permits concentration on only thatspecies. Rhinoceros Iguanas representwhat the British refer to as “largeiguanas.” The Royal Zoological Societyin London and Chester Zoo (North ofEngland Zoological Society) both havecolonies of “Rhinos,” as does the BristolZoo in the southwest of England.

The Bristol Zoological Gardenswere founded in 1835 by a group oflocal citizens and opened to the publicin 1836. It is the fifth oldest zoo in theworld and the oldest not in a capitalcity. Over 200 shareholders contributedthe capital that enabled the land pur-chase and zoo construction. Some ofthe descendants of the original share-holders remain connected with the zoo,but their only benefit is free admission.Buildings are scattered across pleasantgardens, a lake enhances the landscape,and winding pathways connect one ani-mal area to another. Principal attrac-tions include okapis, gorillas, tapirs,seals, penguins, and flamingos.

Tim Skelton, Head of Amphibiansand Reptiles, spent five years at theEdinburgh Zoo and has been at Bristolfor the same length of time. As recentlyas 2001, two large Cyclura werehoused in a large room and two smallerindividuals were held in a separate,smaller cage. The larger animals weresuffering from skin problems, likely dueto insufficient access to direct sunlightand an inappropriate substrate.

The pair of large RhinocerosIguanas both hatched in February1980, the female at the Taronga Zoo inSydney, Australia, and the male in theDominican Republic (later sent toTaronga). Both were received fromTaronga in November 1986. Thefemale has laid eggs, most recentlythree years ago; all were infertile. Thesub-adults are both four-year old malesthat were hatched at the Prague Zoo.Efforts to house all four together werenot successful, as the older pair wouldnot tolerate the younger individuals.

A plan to build new outdoor andindoor enclosures for the large iguanasand three Aldabra Tortoises (Dipsochelysdusummieri = Geochelone gigantea) isnow complete. The new house isapproximately 30 m2 in size and is land-scaped with tropical plants. It is ther-mostatically heated and has a cool fanfor hotter days. Windows are automat-ically controlled and the pool has awaterfall. Water is kept at 25°C. Theoutdoor enclosure is roughly 130 m2.Both adult iguanas and the giant tor-

toises have access to this area throughwide “hospital” flaps of thick, transpar-ent plastic; these keep the heat in whenthe animals come and go. The cost ofthis elaborate project was in excess of£50,000 ($82,000), a magnificent sumof money to spend on iguanas and tor-toises, but the result is a fine newexhibit that greatly enhances the visibil-ity of both species.

The keepers have indicated thatthe iguanas’ skin problems are rapidlydisappearing, and that outdoor access

Adult male Cyclura cornuta in the new indoor pen. Photograph by John Bendon.

The entire outdoor enclosure; the large male Cyclura cornuta and an AldabraTortoise are visible. Photograph by John Bendon.

I G U A N A N E W S B R I E F S154 IGUANA Volume 10, Number 4

has led to dramatic behavioral changes— both animals are considerably moreactive and alert, and their appetite hasincreased sharply. Hopefully, access todirect sunlight will also trigger success-ful breeding behavior.

John S. Bendon

Kansas City HerpetologicalSociety Supports JamaicanIguana Conservation

Shortly after the rediscovery of theJamaican Iguana (Cyclura collei) in1991, the Kansas CityHerpetological Society(KCHS) donated fundsto the Hope Zoo tofacilitate the creation ofa captive breeding pro-gram for this criticallyendangered species. This year, theKCHS donated $1500 in continuedsupport of this species and this impor-tant project. The KCHS would like toencourage other regional societies toget involved with important long-termconservation projects and continue tosupport them over time.

David Nieves, KCHS

Anegada Iguana ReleasesOn 5–12 October 2003, 24 Stout

Iguanas (Cyclura pinguis) headstartedat the Anegada Headstart Facility,British Virgin Islands, were releasedinto two very distinct habitat types. Thefirst cohort of 12 (6.6) was releasedinto dense forest over a reef limestonesubstrate on Middle Cay. The area sup-ports a population of iguanas, includingmany large adults. The second group of12 was released in the Bones Bight areanear the Faulkner House, a well-knownlandmark on Anegada. This area sup-ports a fairly robust (by Anegada stan-dards) population of iguanas withnumerous burrows and nests. Thesereleases and subsequent monitoring arebeing funded by the InternationalIguana Foundation (IIF).

Principals involved with thereleases were Rick Hudson (Fort WorthZoo), Kelly Bradley (Dallas Zoo), who,with Glenn Gerber (San Diego ZooCRES), is responsible for monitoringthe iguanas post-release, Lee Pagni, anEducation Specialist hired by the SanDiego Zoo to canvas local opinions and

develop a proactive Education plan, JeffLemm (San Diego Zoo CRES), andJoe Wasilewski (International IguanaSociety), who filmed the event.

A veterinary team from the FortWorth Zoo had previously implantedtransmitters in the abdominal cavities ofthe 24 iguanas. The releases went welland seeing some local residents assistwith the releases was gratifying. TheNational Parks Trust staff was there withthe local media. Coverage in the local

newspapers was good, and internationalcoverage included CNN News Online.

Bradley and Lemm remained on-site for several days after the releases andthey reported visual sightings of theiguanas every other day. The iguanasappear to be settling in and not movingfar (except for two). Rondell Smith(Trust employee) will track the animalsweekly while Bradley is off-island.

This event was significant in thatthe headstart program has now come

An adult Cyclura collei in the breeding facility at Hope Zoo in Jamaica. Successfulbreeding remains a challenge, but the proposed upgrade to these enclosuresholds promise for the future. Photograph by John Binns.

Post-release Cyclura pinguis surveying his surroundings from a dead Loblolly Treeon Middle Cay. Photograph by Rick Hudson.

I G U A N A N E W S B R I E F S155IGUANADecember 2003

full circle: one of the three iguanas ini-tially placed in the headstart facility byHudson and Lemm in 1997 was one ofthe first animals released. The plan is toestablish a regular cycle in whichiguanas are released each year toaccommodate the new hatchlings col-lected in October. This year just over20 hatchlings from marked nests wereplaced in the facility.

The headstart facility is in excellentcondition. The iguanas appear robust,healthy, and well-fed. The gardens arewell-kept, with lots of iguana foodbeing grown by the primary caretaker,Lee Vanterpool, who also collectsnative iguana food plants to supple-ment their diet.

Rick Hudson, Co-chairIguana Specialist Group

The IIS in SeattleJoe Wasilewski, Joe Burgess, and

John Binns represented the IIS this fallat the Pacific Science Center in Seattlefor the Northwest HerpetologicalSociety’s “Reptiles Around the World.”The two-day educational event wasattended by reptile enthusiasts, begin-ners, and the curious. The IIS contin-gent promoted iguana conservationand responsible pet ownership. Izzy,John’s large Cuban Iguana (Cyclura

nubila), became the star of the event,drawing admirers to learn more aboutthis spectacular animal. Joe W. con-ducted several reptile shows formuseum guests and demonstrated howa cute little iguana or snake can grow tobe a powerful animal that can rapidlyoutgrow its home. He also discussedwhat types of reptiles would orwouldn’t make good pets and graphi-cally described the consequences of animpulse buy.

Mexican Iguana Group isOnline

Information about the activities ofthe Subcomité Técnico Consultivo parala Conservación, Manejo y Aprove-chamiento Sustentable de las Iguanas inMéxico (Advisory Technical Sub-committee for the Conservation,Management, and Utilization of Iguanasin Mexico) is available on the Sub-committee’s new webpage (http://www.subcomitedeiguanas.org/).

Victor Hugo ReynosoDepartamento de Zoologia

Instituto de Biologia, UNAMMéxico, D.F.

The IIS table at the Pacific Science Center.

The IIS contingent in Seattle: Izzy, John Binns, Joe Wasilewski, and Joe Burgess (leftto right).

Jeff Lemm and Kelly Bradley areshown tracking newly releasedCyclura pinguis from the back of atruck for elevation in the Bones Bightarea. Photograph by Rick Hudson.

I G U A N A N E W S B R I E F S156 IGUANA Volume 10, Number 4

The IIS and IguanaEducation

IIS members John and SandyBinns visited the Boys & Girls Club ofthe Peninsula in East Palo Alto,California and shared the iguana expe-rience with over 140 children rangingin age from 6–14 years. Topics includeda general overview of reptiles, dailystruggles specific lizards face both inthe wild and captivity, human percep-tions, and conservation efforts in thepast, present, and future. The childrenwere excited and full of questions, asmany of them had never seen or evenheard of these animals. Each child hadthe opportunity for an up-closeencounter with several different speciesincluding Green, Cuban, and Rhinoiguanas, Spiny-tailed Dwarf Monitor,Uromastyx, Chuckwalla, and Blue-tongued Skink.

Sandy Binns

First Blue IguanaSponsored in 2003

The John Gray Recyclers, a highschool club on Grand Cayman Island,became the first sponsor of a BlueIguana (Cyclura lewisi) hatched thisyear. The club, which promotes recy-cling, raised over US $900 to name andsponsor “Quincy” for a year. The namecomes from “quincentennial,” acknowl-edging the 500th anniversary of the“discovery” of the Cayman Islands,which is being celebrated in 2003.

Quincy, who will keep the namepermanently, is a very special littleiguana; he was born with an incompleteforelimb on one side. The money raisedwill help support Quincy and his sib-lings as part of the Blue IguanaRecovery Program and help ensure thesurvival of the most endangered reptil-ian species on earth. For more informa-tion on the sponsorship program, seewww.blueiguana.ky.

The Boys & Girls Club of East Palo Alto, California were delighted by a visit fromJohn Binns (front row, holding an iguana) and Sandy Binns (front row, right).

Quincy is one of a record 84 Blue Iguanas hatched this year at the captivebreeding facility on Grand Cayman. Photograph by Fred Burton.

I.I.S. Board of DirectorsJoseph Wasilewski, PresidentHomestead, FL

Joseph Burgess, Vice-presidentJacksonville, FL

A.C. Echternacht, Ph.D., TreasurerUniversity of Tennesee, Knoxville, TN

AJ Gutman, Executive Secretary andAssociate Editor of IGUANAWest Harford, CT

John & Sandy Binns, Directors, AssociateEditors of IGUANA and Internet OperationsInternational Reptile Conservation Foundation,San Jose, CA

Gunther Köhler, Ph.D. and Elke Köhler,DirectorsForschungsinstitut und NaturmuseumSenckenberg & Herpeton, Frankfurt, Germany

Robert Powell, Ph.D., Director and Editorof IGUANAAvila University, Kansas City, MO

I.I.S. Editorial/AdvisoryBoardAllison C. Alberts, Ph.D.IUCN/SSC Iguana Specialist Group andZoological Society of San Diego, San Diego, CA

John Bendon, Illustrator for IGUANABath, England

Gordon M. Burghardt, Ph.D.University of Tennessee, Knoxville, TN

Frederic J. BurtonBlue Iguana Recovery Program, Grand Cayman,Cayman Islands

Jorge FerrariOrganización de Rescate y Protección deReptiles y Anfibios, Tegucigalpa, Honduras

Matthias Goetz, Dipl.-Biol.Durrell Wildlife Conservation Trust, Jersey,British Isles

Alexander Gutsche, Dipl.-Biol.Humboldt Universität, Berlin, Germany

Richard HudsonInternational Iguana Foundation and Fort Worth Zoo, Fort Worth, TX

John B. Iverson, Ph.D.Earlham College, Richmond, IN

Chuck KnappUniversity of Florida, Gainesville, FL

Michael Ripca, Managing Editor of IGUANALeaping Lizards Graphic Design, Atco, NJ

Thomas Wiewandt, Ph.D.Wild Horizons, Tucson, AZ

FounderRobert W. EhrigBig Pine Key, FL

Statement of PurposeThe International Iguana Society, Inc. is a not-for-profit corporation dedicated to preserving the biological diversity ofiguanas. We believe that the best way to protect iguanas and other native plants and animals is to preserve naturalhabitats and to encourage development of sustainable economies compatible with the maintenance of biodiversity. Tothis end, we will: (1) engage in active conservation, initiating, assisting, and funding conservation efforts in coopera-tion with U.S. and international governmental and private agencies; (2) promote educational efforts related to thepreservation of biodiversity; (3) build connections between individuals and the academic, zoo, and conservation com-munities, providing conduits for education and for involving the general public in efforts to preserve endangered species;and (4) encourage the dissemination and exchange of information on the ecology, population biology, behavior, cap-tive husbandry, taxonomy, and evolution of iguanas.

Membership InformationIguana, the Journal of The International Iguana Society, is distributed quarterly to members and member organizations.Annual dues:Individual U.S. and Canadian Membership . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $25.00Individual Foreign Membership . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $35.00U.S. and Canadian Organizational Membership* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $35.00Foreign Organizational Membership* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $45.00

(*receives double copies of Iguana) Additional copies are available at a cost of $6.00 including postage.

JOIN ON-LINE AT: www.IguanaSociety.org

Membership questions? Call AJ at 860-236-8203, or write to: The International Iguana Society, Inc., 133 SteeleRoad, West Hartford, CT 06119

SolicitationsMembers of the I.I.S. are encouraged to contribute articles, letters to the Editor, news items, and announcements forpublication in IGUANA. General articles can deal with any aspect of iguana biology, including conservation, behavior,ecology, physiology, systematics, or husbandry. Submission of photographs to accompany articles is encouraged.

Manuscripts may be submitted via e-mail (send to [email protected]). For any contribution, please include your name,address, phone number, and e-mail address. Authors of one page or more of print are entitled to five copies of the issuein which their article appears.

Advertising Policy of IGUANAWe advertise only non-living products (except feeder insects). All products have been examined and been found to behigh quality and fairly priced. Contact Sandy Binns, Advertising Director, at [email protected] or 3010 Magnum Drive,San Jose, CA 95135.

IGUANA Copyright ©2003 by The International Iguana Society, Inc., 133 Steele Road, West Hartford, CT 06119 USA. ISSN # 1098-6324. The contents of IGUANA, excluding Research Articles, Research Updates, andreprinted articles, may be reproduced for inclusion in the newsletters of other herpetological societies, provided the material is reproduced without change and with appropriate credits, and a copy of the publication issent to The International Iguana Society. Occasional exceptions may be made to this policy.

Editors’ RemarksConservation of iguanas and their habitats is the principal component of the IIS Statement ofPurpose (printed in full just below this note). That also has been a recurring theme in every issueof the Iguana Times and will continue to be the predominant message in IGUANA. However,conservation is not merely something about which to write and read. Conservation requiresaction in the form of education, financial support, and sometimes even getting one’s handsdirty. The IIS is actively engaged in all of those endeavors. In the past few months, representa-tives of the Society have carried an educational message from coast to coast: from Jacksonville,Florida to Seattle, Washington and East Palo Alto, California (see Newsbriefs in this and the pre-vious issue of IGUANA). The Society has provided financial assistance to aid in developing a cap-tive breeding program for Jamaican Iguanas at the Hope Zoo in Kingston (see Newsbriefs). Weare monitoring and working closely with conservation agencies and organizations concernedwith iguanas. Most recently, IIS representatives participated in the IUCN/SSC Iguana SpecialistGroup (ISG) meeting in the Turks and Caicos Islands, which included a Conservation &Management workshop for Cyclura carinata (a full report will be featured in the March issue ofIGUANA). And IIS members prove again and again that they’re willing to dirty their hands forworthy causes; see, for example, the Newsbriefs and the Letter from the President. Althoughevery individual involved pays his or her own way or is supported by their home institution, theIIS message they spread is possible only through the support of the Society’s members. Even ifyou have never stood in front of an audience and talked about iguanas, written a check to sup-port an iguana conservation program, or traveled to the tropics to study or monitor a popula-tion of iguanas, you are a vital link in these efforts.

Bob Powell, AJ Gutman, and John Binns


L E T T E R F R O M T H E P R E S I D E N T

I’ve had the pleasure of some enriching momentsduring my 25-year career in wildlife conservation, work-ing with a variety of reptiles, as well as Bald Eagles(Haliaeetus leucocephalus) and Ospreys (Pandion hali-aetus). Over the years, I have captured, marked, andreleased well over three thousand American Crocodiles(Crocodylus acutus). Being able to release these endan-gered animals is extremely fulfilling, despite knowingthat only 5–10% of them will survive the first year. Ofthe crocodiles that do survive, some will undoubtedlyexpand their range and, in some cases, encroach onpopulated areas. The available natural habitat of thecrocodile is shrinking daily. Future interactions betweenhumans and crocodiles are inevitable and educatingpeople before such interactions take place is crucial.

Many of the same factors that cause eagles andospreys and crocodiles to be endangered affect the var-ious species of Cyclura throughout their respectiveranges. In February 2001, I traveled to Jamaica withRick Hudson of the Fort Worth Zoo to assist in therelease of 13 Jamaican Iguanas (Cyclura collei). Weaccompanied Byron Wilson into the Hellshire Hills, theremaining natural range of the species. This particularevent brought the number of head-started and releasedanimals to 39. While the news may be encouraging forthe Jamaican Iguana, the obstacles they face have notreally changed: shrinking habitat, feral predators, andlimited resources. Much work is still necessary to assistthe iguanas and increase their population in theHellshire Hills.

That story, however, brings me to another “happyending” — the historic release of 24 head-started StoutIguanas (Cyclura pinguis). In October 2003, I accom-panied Rick Hudson, Jeff Lemm of the San Diego Zoo,and Kelly Bradley of the Dallas Zoo to the island ofAnegada in the British Virgin Islands. The 24 oldestiguanas from the head-start program were selected,health screened, processed, and readied for release.Even with 24 new adult and sub-adult iguanas in thepopulation, the threats, like those in Jamaica, remainthe same. This time, however, the people of Anegadaare making plans to eliminate the feral cat problem, andactually want to focus on preserving some of the corehabitat. Time will tell if these measures will bring aboutpositive results.

The emotions that come into play while releasingendangered animals are difficult to describe. I try toinclude people from all walks of life to assist in thereleases and share in the experience. You actually have asense of giving back and getting closer to nature. In

some small way, you are helping to preserve a speciesfor posterity. For just a few moments, you watch inamazement and forget all the obstacles these animalswill face. The iguanas don’t just bolt away; they walk abit, taste the ground, look up at you, maybe give a headbob or two. They seem at home and take their timewalking away.

Even though we are now returning some of theseanimals to the wild, our work is not finished — instead,it has only just begun. All of the threats that broughtthese species to their current states still exist, and con-servation organizations around the world must worktogether to preserve these animals for future genera-tions.

The International Iguana Society is working withmany organizations to make this a better world. If youknow people who should join the society and help inthis worthwhile endeavor, sign them up!!!

Joe Wasilewski

Joe Wasilewski, IIS President, participating in the release onMiddle Cay. Photograph by Rick Hudson.

A feral Green Iguana (Iguana iguana) in Florida (story on p. 111). Photograph by Joe Wasilewski.

iguana volume 10, number 4 december 2003 us$6 · a lthough the banded iguana (brachylophus...

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