Keeping Reptiles Newsletter
 
  Issue 1 January 2008
What is a Venomous Snake Anyway? In this Issue

By J. DeRyke

Venom, venomous, and non-venomous snakes and the problems associated with keeping such creatures are somewhat magnified by the venomous variety's reputation. But what is a "venomous" snake anyway? The dictionary's definition is 'a creature having a poison-producing gland and able to inflict a poisoned wound.' That, as we shall see, covers a very broad area.

Snakes have rather slow metabolisms as befitting their slow life-style. They don't eat very often, and when they do, the meal is likely to be relatively huge. This is abetted by not having any limbs with which to tear chunks off, so all meals will be whole animals. Chewing is not effective either, so the digestive juices are not forced into the prey and its surface area is not increased by chewing or tearing.

Once swallowed, a prey animal being large will slow the maneuverability and speed of a

Inland Taipan or Fierce Snake
The most venomous snake in the world (although no the most deadly).A single bite from the Inland Taipan or Fierce Snake contains enough venom to kill as many as 100 human adults, or 250,000 mice.

successful snake. This makes just fed snakes vulnerable to attack by their own predators. Prey animals such as rodents often have tough skins, further slowing digestion and prolonging the vulnerability of a just-fed snake. Nature, in her attempts to help the situation, equipped the snake with powerful digestive juices to speed up digestion. And in many species, the saliva not only lubricates the prey so it goes down the snakes throat easier, but the saliva itself is a powerful

Research has shown that 'venom' is primarily a digestive medium from highly modified saliva glands. It immediately starts cell breakdown and in some types, actual liquefaction of tissue. The fact that venom also kills the animal it’s applied to seems almost a byproduct, even though some snakes (vipers for instance) have evolved to take full advantage of it more than others. The kicker is, most animals have pre-digestive juices in their mouths, humans included. Some secretions are more powerful than others, and some are quicker acting than others.

For instance, all colubrid snakes including garters, racers, and corn snakes have a Dunevoy's gland that feeds its secretions into the snake's mouth during feeding. Some, such as the hognose snake, have specialized, enlarged rear teeth used to deflate puffed-up toads or frogs and deliver these secretions into the animals body. This 'enlargement' produces a pair of back teeth around 0.050" long. And while the hognose oral secretions do not kills its prey, it does seem to quiet them almost like a sedative, making swallowing less of a battle.

So, are Colubrids venomous? Almost all authorities say no, but a few say, "Well.…it depends…" A humans reaction to venom seems critical to the definition as it now exists. And we all know that, somewhere, someone will react allergically to almost anything including milk and peanuts -- two things not normally thought of as poisons. It turns out to be quite difficult for medical technicians to separate 'anaphylactic' shock from a sensitized material and a true venom reaction.

Again, the dictionary waffles a bit: 'anaphylaxis:hypersensitivity (as to foreign proteins or drugs) resulting from sensitization due to prior contact with the causative agent.'

Indeed, this has caused problems with venomous snake-wranglers that have already been bitten and received antivenin. Anaphylactic shock occurs when a once-bitten and treated human reacts more strongly to anti-venom proteins than to the snake venom itself. Nowadays, people who are snake-bitten and rushed to a hospital do not automatically receive antivenin shots, especially if the snake that caused the problem is not present for examination.

Rather than sensitize you needlessly, injecting you with unneeded anti-venin, then risking throwing you into cardiac arrest from anaphylactic shock, they wait to see what happens. It is not much fun. Ok, back to the subject, what is a venomous snake?

My definition is, "any one that can kill you." It would be foolish to exclude known killers such as rattlesnakes, copperheads, moccasins, and the coral snake. However, if you happen to be sensitive to bee or wasp stings, spider bites, or maybe mosquitoes, it may pay to steer clear of big snakes known to possess a Dunevoy's gland. This will include False Water Cobras, Giant Garter snakes, Madagascar Giant Hognoses, and Jewelled Ratsnakes.

Large examples of the foregoing species simply carry more volume of their secretions than small ones. Also, their teeth are longer, making it more likely you will get some of the secretions in a wound.

 

Reprinted from the newsletter of the St. Louis Herpetological Society, Vol.38, No.10, October 2005

 

Note: There is an interesting article on recent research on venom in lizards that has changed much of what we know in this edition of Keeping Reptiles. There is also an article that discusses toxicity in this edition.

  1. What is a Venomous Snake Anyway?
  2. Veiled Chameleons
  3. In the News
  4. Get Paid to write an article
  5. Tell Us What You Think
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Veiled Chameleons

By Eric Adrignola

Before the first veiled chameleons were imported, captive-bred chameleons were a rarity. In just a few years, however, the number of captive born and bred C. calyptratus exceeded the number of imported animals. Thousands of veiled chameleons are produced every year in the United States alone. They have become the most popular pet chameleons. Famous for their intense coloration and unusually large helmet, or casque, veiled chameleons have permeated the pet industry. However, it is not due to their desirability alone that they have succeeded in captivity.

Chamaeleo calyptratus, better known as the veiled, or Yemen chameleon, is a large, colorful lizard. The common name, "veiled" chameleon comes from the scientific name, calyptratus. This name is derived from their distinctive casque. The tall hoodlike crest on their heads resembles a calyptra, or veil, which is a structure on some mosses and lichens. They are native to Saudi Arabia and Yemen. Despite corning from a region that is one of the most arid on earth, they are not purely desert creatures. C. calyptratus are most often found in tropi.cal oases. These areas often have higher humidity and more plant life than the surrounding desert and are subject to extremes in temperature and humidity. Daytime temperatures can be well over 100 degrees. Nighttime temperatures can drop to below freezing on occasion. This drastic difference causes dew to form on plants, providing a source of moisture for the chameleons. C. calyptratus can tolerate a wide range of climates and conditions. Veiled chameleons are very tough, adaptable animals. They are quite different from many other species of chameleons, which only have a narrow tolerance for temperature and humidity. It is because of this adaptability that veiled chameleons are better able to thrive in captivity compared to most other chameleon species.

Captive Housing
The enclosure should be a minimum of 2'x2'x3' tall, and contain live plants and dry branches for basking spots. It should be as high as possible, especially for adult males. When smaller cages are used, they should be raised several feet above the ground. For juveniles, fake plants are fine. However, as they mature, veiled chameleons will begin to eat vegetation, live or not. They will choke on fake plants, so it's best to remove them after the lizard reaches six months of age. Lighting should consist of an ultraviolet light and a basking light. The basking light should be a 60W bulb for juveniles and a 75-100W bulb for adults. Fluorescent bulbs provide UVA and UVB light. UVA is found in all full-spectrum bulbs, while UVB is only found in adequate quantities in specially made reptile bulbs. One of each is recommended. The basking lamp should maintain the proper temperature. A basking temperature in the high 90's is ideal. Lower portions of the cage should be in the 80's to allow the chameleon to thermoregulate. Take care to ensure the chameleon cannot get close enough to the bulb to burn itself.

They do not know when they are burning, so it's up to you to make sure they can't. Thermal burns are the #1 injury to captive-bred chameleons. Do not use any form of heating at night. As long as temperatures stay above 50 degrees, there is no reason to heat the cage at night. Temperature drops are beneficial to a chameleon's metabolism.

Female Chameleo calyptratus
male Chameleo calyptratus
Female Veiled Chameleon
Male Veiled Chameleon

 

Nutrition
Veiled chameleons will eat almost any bug you can find. The gray cricket is the most common feeder insect available, and will make up a good portion of the chameleon's diet in captivity. Other commercially available insects are superworms, silkworms, mealworms, waxworms, butterworms, hornworms, flies, and roaches. Variety is important. Chameleons need to consume a number of different insects to stay healthy. It is also important to feed your insects a good diet (called "gut loading") prior to feeding them to the chameleons.

Veiled chameleons are always hungry. They'll make you think they're about to die of starvation by the way they act towards food. Veileds do not need to eat nearly as much as they will eat -- kind of like us. Chronic overeating leads to shortened lifespans in both sexes. Overfed females will produce massive clutches of eggs. They usually do not live more than two years. Overfed males will have fat sticking out of the back and sides of their head. This means there is even more fat tissue on their internal organs. Fatty liver disease kills quite a few otherwise healthy animals. Male veileds have lived over 10 years in captivity, although six to eight years is more common. Overfed males seldom live more than three years. Females can live from four to six years, but heavy breeding shortens their lives.

Calcium supplementation is necessary for chameleons kept indoors. Without sunlight, they need an artificial source of D3. Artificial UVB lighting is helpfut but not enough by itself. A calcium/ mineral supplementation with D3 is needed to grow strong bones. Young veileds should get supplemented every day, adults need it every week or so. Providing vitamin/ mineral supplementation is simple: Simply coat feeder insects with the powder prior to being fed to the chameleon.

Vegetation is an important part of the diet of adult veiled chameleons. In the wild, they will eat plants to get them through lean times. In captivity, they will eat a variety of fruits and vegetables. Feeding plant matter helps control obesity. Hibiscus blossoms, red grapes, strawberries and dandelion flowers are a favorite, though they'll eat almost anything, including their furnishings!

Humidity and Hydration
Veiled chameleons do not require as much water or as high humiility as other chameleons. As previously mentioned, they are not true desert animals. Humidity levels in nature are generally fairly moderate, especially at night. In the wild veiled chameleons endure very dry conditions, but this is not their preferred situation. High levels of humidity and lack of ventilation will lead to skin infections and respiratory problems. An easy way to maintain proper levels of humidity is to keep the live plants in the cage well watered. Daily misting will also help keep the humidity level high enough. Occasional heavy misting or showers are important, as it allows the chameleon to clean out its eyes.

Water should be provided in a drip system. This is especially easy when live plants are used. A small plastic deli cup is poked with a needle or thumbtack. The container is filled with water and placed so that it drips onto the plants in the cage. The chameleon will drink from the leaves and any excess water is taken up by the plant. You'll never have to water the plant. Juveniles should be watered every day by heavy misting. Adults should get drip-watered every day or every other day depending on the temperature and humidity. If it's been exceptionally hot and dry, they'll need more water.

 

Eric Adrignola is a graduate of North Carolina State University with a Bachelor's Degree in Zoology. He has over 10 years of experience with chameleons.

Reprinted from "The Cold Blooded News" the Newsletter of the Colorado Herpetological Society, Volume 33, Number 4;   April, 2006

 

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