Download - WRHA Newsletter August 2011
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Monthly Newsletter
August 2011
From the Editors Desk
By Timothy Zedi
This month I will be focusing the introduction of reptiles and amphibians to countries
where they do not occur naturally ( alien species) .I have included situations were
invasive reptiles have caused massive damage as well as a few interesting places reptiles
have been relocated to. I have written an article on the factors which,would effect thesuccesfull introduction of exotic reptiles into South Africa. I have chosen a few of the
most commonly kept species as well as some exotic species that are banned, I ask thequestion are some of these animal not as invasive as nature conservation makes them outto be. I have included a summary of the presentation that Wendy Willson of the NSPCA
gave at the last meeting.
Official West Rand Herpetological Association Website
http://www.wrha.co.za/http://www.wrha.co.za/ -
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The Invasion of Guam
The island of Guam lies in the Western Pacific and is near Australia. The Americans have
an air force base on the island and used it to attack the Japanese during the Second World
War. Along with the bombs, bullets and ration packs the Americans flew in from
Australia during the war, they bought some unwanted stowaways. The Australian BrownTree Snake, a mildly venomous backed fanged snake was introduced with the cargo. As
Guam has no indigenousness snakes, plenty of birds, lizards and rats this snake species
had the perfect location in which to launch its attack. The snakes gradually spread troughout the island and by 1982 they could be found all over the island except in small areas of
savanna where they cannot survive. The population of several species of forest bird began
to decline after the arrival of the snake. All 10 forest species are now in trouble withmany extinct and others with extremely low populations under 100 in some cases. Apart
from birds the snakes eat skinks, geckos and even domestic chickens. The snakes cause
power cuts by climbing onto overhead electrical cables. There have been cases of attackson sleeping children usually between the ages of 1 to 2 months. Some of these injuries
seem to be from attempts to eat the children ( there has been no case of this snake killingand swallowing a child). Brown Tree snakes are too small to eat children anyway but
thats what the researches say, who are we to question. So why did the Brown Tree snakecause so many problems? Firstly it had very few predators on the island, so a large
population could be established. Secondly the forest canopy on Guam is low and birds
are unable to find safe places to roost and nest to protect them from the snakes. Thirdlythere is an alternative food source on the island in the form of lizards that the snake can
eat once the birds become extinct in an area, therefore the snakes will not starve to death
and population levels can be maintained. The situation on Guam is serious and should notbe taken lightly and is a stark reminder not to release snakes into the wild. Ironically it is
often rats and pigs which cause the most damage on islands by eating reptile and bird
eggs as well as fledgling birds.
Island of Guam Australian Brown Tree Snake
(Boiga irregularis)
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Hawais African Immigrant
There are no native species of chameleon in the new world ( North America, Central
America, South America and the West Indies). You may have heard the term American
Chameleon this refers to a group of lizards known as Anoles. Anoles can only darken
and lighten their skin e.g Green Anoles can change from green to brown, but cannot alterpattern and colour for display or to blend into surroundings. Technically Chameleons use
their colour changing abilities mostly for display and have a default colour for
camouflage that can be altered to match their surroundings , but not to the degree mostpeople think. The island of Hawai has no native chameleons. For many years the
Jacksons Chameleon from Uganda and Tanzania was a popular pet in the US before the
succesfull breeding of Veiled and Panther Chameleons. Jacksons Chameleons look likeminiature dinosaurs with the males having three horns used for combat with other males
during breeding season, this makes them very sort after. Unfortunatley most Jacksons
Chameleons were wild caught and imported to the US. Some clever reptile dealer inHawai imported some of these chameleons, they had arrived in a bad condition so he put
them in his garden to recover. Of course the chameleons escaped and thrived in Hawaistropical environment. Jacksons Chameleons do not pose a significant effect on the
environment in Hawai. An interesting fact is that Hawai has no native frog species,however the Pacific Tree Frog has been introduced onto the island. It to dos not pose a
significant threat either. For those of you who dont know Hawai is a state of America.
So in a round about way the Jacksons Chameleon was introduced within the borders ofthe US.
Jacksons Chameleon ( Chamaeleo jacksonii)
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Cane Toad Chaos
I would like to state that Australia has the worst environmental impact record of anyWesternized country in the last 200 years. The Australians environmental crimes include
the intentional introduction of invasive species, these include rabbits, foxes, camels, pigs,donkeys and of course Cane Toads. Cane Toads which originate from South America
were introduced in 1935 into Australia. Three Thousand toads were released into
Queensland; the population of Cane Toads in Australia is now estimated at several
million toads. The toads were introduced to try to eliminate the indigenousness canebeetle which was causing damage to sugar cane plantations. Adult Cane Toads grow to
25cm in length, an adult Cane Toad needs much larger prey than cane beetles. The adult
toads began to eat small marsupial rodents ( type of small marsupial about the size of arat and native only to Australia), small lizards, frogs, small snakes as well as rats and
mice. The real problem with the Cane Toads is that they secrete a poison from an organknown as a parotiod gland which is fatal to animals that try to eat it. The poison does notusually kill humans. Cane Toad eggs and tadpoles are also poisonous. In their native
habitat certain predators have gained immunity from the toads poison, these predators
keep the toads population in check. Australian toad eaters such as: monitor lizards,
snakes, crocodiles, mammals and birds are not immune and die after eating a Cane Toad.This ends up in a large drop in the populations of these predators. It is almost impossible
to stop the Cane Toad invasion, a female Cane Toad can have up to thirty thousand eggs
all of which cannot be eaten. Even Australian citizens are encouraged to kill any CaneToads that they come upon. It took the introduction of a virus to stop rabbits breeding out
of control, maybe something similar will be used on the Cane Toad or the Australian
government may introduce another species to kill off the Cane Toads. The case aboveproves that trying to solve problems using biological methods is a gamble and gambling
with the natural world is a very dangerous game.
Cane Toad (Bufo marinus)
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The Naming Game
Here is a quote from a retired field herpetologist from the Californian Academy of
Science ( Steinhart Aquarium)
At best, the continued upheaval within the taxonomic community, never agreed by all
and a nightmare to be sure, has only created a barrel of confusion. I fear it will never end.Therefore, stick with that which has stood the test of time. And to put it in understandable
perspective, a rose by any other name is still a rose
Bellow is the method I have formulated to remember scientific names. I have used it
for many years and would like to share it with you just for interest sake.
I have found that the easiest way to identify a snake by its scientific name is to remember
the genus name allowing me too identify the group e.gElaphe are Rat Snakes,Lampropeltis are King Snakes. Then remember the species name then add it to the genus
name e.gElaphe obsolete are American Rat Snakes,Lampropeltis getulus are Common
King Snakes,Lampropeltis triangulum are Milk Snakes. The only problem with this
system is that subspecies names must be remembered individually (there are 25subspecies of Milk snake!!). I find this method easy to use, however it becomes difficult
when the name of a snakes genus has been changed, therefore I stick to the names I know
as stated by the quote above.
As it is impossible to remember every genus of snake, I have memorized the names of the
snakes that are the most common.
Example
Bitis: African Adders
Crotalus: Rattlesnakes
Naja: Cobras
Bothrops: South American Pit VipersTrimeresurus: Aboreal Asian Pit Vipers ( White Lipped Tree Viper)
Cerates: Saharah Horned Viper
Lampropeltis: King Snakes & Milk SnakesElaphe: Rat Snakes
Vipera: European Vipers.
Morelia & Liasis: Australian PythonsHeterodon: North American Hognose Snakes
I also find it useful to group these snakes into geographical areas.
Please Contact me if you have your own system and I will publish it in the newsletter.
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