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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wrha newsletter august 2011

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