That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

Today we’ll take another look at those oddest of lizards, the chameleons (Family Chamaeleonidae), followed by some tips on the care of the Senegal Chameleon (Chamaeleo senegalensis).

Eyes

The cone shaped torrents that enclose the chameleon’s eyes are actually made up of fused, overlapping sets of eye lids.  By covering all but the eye’s pupil, they offer excellent protection to this most important organ.

Chameleon eyes contain far more visual cells than do our own, and can be rotated 180 degrees.  Uniquely among all animals, the eyes can focus either independently (on different objects) or together.

Vision, Learning and Hunting Accuracy

When a chameleon focuses both eyes on an insect, it hits its target 9 out of 10 times.  In laboratory situations, accuracy falls to 0 when 1 eye is covered.  However, by the second day hunting accuracy rises to 20%.  On day 4, the one-eyed hunters successfully capture insects on 50% of their attempts.

Senses of Hearing and Smell

Chameleons do not hear well …like snakes, they detect air vibrations and low-pitched sounds only.

The Jacobsen’s organ, which allows many other reptiles to “smell” chemical particles in the air, is vestigial (much reduced) in chameleons.  It is therefore assumed that they do not detect most odors.

Distribution

Madagascar is the center of chameleon diversity, with over 75 species, many endemic, living there.  Neighboring Africa, despite being vastly larger, boasts only 100 or so species.  Only 2 species make their homes in the Middle East, 2 in Europe and 2 in India and Sri Lanka.

At least 2 species of chameleon have established feral populations in foreign habitats.  The veiled chameleon (Chamaeleo calyptratus) thrives in Florida, Hawaii and Mexico, while the Jackson’s chameleon (C. jacksonii) has been breeding on Hawaii since the 1970’s and has recently been discovered in California.

The Senegal Chameleon, Chamaeleo senegalensis

Hailing from tropical West Africa (Senegal to Cameroon), this dark-spotted, tan to olive chameleon inhabits brushy savannas and forest edges.  Often abundant and easy to collect, it has long been a pet trade staple.

Some Cautions

Despite its long history in captivity, the Senegal does not breed regularly, and presents some problems as a pet.  Wild caught specimens should be avoided, as they are usually heavily parasitized and afflicted with stress related ailments.

Captive Environment

Senegal Chameleons need quite, heavily planted screen cages or an outdoor aviary , abundant UVB radiation and should be kept well-hydrated via frequent spraying or the use of a mister.  An ambient temperature of 76F with a basking site of 85F and a nighttime dip to 69-70F suits them well.

Breeding

If you are lucky enough to obtain a breeding pair, you’ll have your hands full…healthy females may lay 20-70 eggs at a time, twice each year!  Incubation time averages 6 months at 77 F, and sexual maturity may be reached by 5 months of age.

The Smooth Chameleon

The range of East Africa’s Smooth Chameleon overlaps that of the Senegal in Cameroon.  Formerly classified as a subspecies, the smooth chameleon has now been given full species status as Chamaeleo laevigata.

Male Chameleon in Madagascar image referenced from wikipedia and originally posted by Mbz1
Veiled Chameleon in Madagascar image referenced from wikipedia and originally posted by Billybizkit

After shedding, leopard geckos (Eublepharis macularius) sometimes exhibit a condition that superficially resembles what snake owners know as “retained eye caps”. However, the structure of a leopard gecko’s eye, and that of the closely related banded and fat-tailed geckos, is nothing like that of a snake’s, and problems following shedding must be addressed in a very different manner.

Leopard Gecko Eye Structure

Leopard, banded and fat-tailed geckos are classified in the gecko subfamily Eublepharinae, and differ from all other geckos in having movable eyelids. In fact, the genus name, Eublepharis, means “true eye lids”. The eyes of all other species in the family Gekkonidae are covered by a transparent cap, or spectacle, which is fused to the eyelids (like snakes, they cannot blink their eyes).

The eyelids of leopard geckos and their relatives are lined with a thin layer of skin. This eyelid liner is replaced along with the rest of the gecko’s skin when shedding occurs. However, if conditions are too dry in the terrarium, the eyelid lining may stick to the lid and be retained after shedding. This will lead to an irritation. Eventually, an infection will set in and cause the eye to swell.

Diagnosis and Treatment

The retained skin is thin but visible, so check your gecko carefully after it sheds. Geckos so affected will also blink a great deal, and may rub the area.

While experienced hobbyists may be able to remove retained eye caps (brille) from pet snakes, retained eyelid liners are an entirely different matter. This problem must be attended to by an experienced veterinarian only.

Avoiding Problems: Humidity and Diet

An overly-dry environment seems to be the main factor leading to retained eyelid liners. Although geckos are native to quite arid habitats, like all desert animals they are able to find moist retreats, usually below ground, when necessary. It is easy to overlook this when keeping desert animals. For years zoos kept Gila monsters, native to one of the driest places on earth, in bone-dry exhibits. Field research showed, however, that these lizards actually spend 90% of their time in burrows where humidity levels are quite high.

Shedding aids are useful for lizards of all types, especially desert-adapted species.

Low Vitamin A levels have also been implicated in gecko shedding problems. Be sure to provide your lizard with a varied diet and appropriate vitamin/mineral supplements. Please write in if you need detailed advice on feeding your gecko.

In direct contrast to popularly-held theories, researchers at Australia’s University of Melbourne believe that the need to rapidly signal other chameleons, and not the need to hide from predators, has driven the evolution of the amazing color-changing abilities possessed by these lizards.  In a sense, the primary function of color change is to render the animals more conspicuous – the opposite of being well-camouflaged!

Camouflage

However, the need to camouflage still exerts an influence.  By being able to affect color changes in a mere fraction of a second, the lizards lessen the chance that predators will notice them.

Earlier research at the University of Melbourne has also revealed that at least 1 species does endeavor to “match” the background upon which in rests.  In fact, Smith’s dwarf chameleon actually alters the degree of color change it exhibits in response to the type of predator it faces (please see article below).

Other Possibilities: My Experience

I have noticed that, unlike most animals that display (male birds, for example, often sing for hours on end, even if when other birds are not visible), chameleons only flash messages when in the presence of possible rivals or mates.  This would also seem to limit their exposure to predators.

Chameleons also display an incredible range of subtle color variations, most not visible to the human eye which, I believe, also assists in “getting their message across” as quickly as possible.

Further Reading

To learn more about new research regarding color change and predator avoidance, please see my article Chameleons and Camouflage.

 

Please see Part I of this article for more on bent-toed geckos (Genus Cyrtodactylus; C. louisiadensis and C. irianjayaensis).

UVB and Calcium
Although nocturnal, assume that bent-toed geckos require UVB radiation (others in the genus seem prone to metabolic bone disease). As these lizards generally do not bask at very high temperatures, a fluorescent bulb is preferable. Among florescent models, the Zoo Med 10.0 Bulb  has been shown to consistently deliver the highest UVB output.

To cover all bases until we learn more, I suggest adding extra calcium (along with Vitamin D3) to all food offered. A high calcium supplement can easily be fashioned by mixing Reptivite and Zoo Med Repti Calcium  together in a 1:1 ratio. While this step has not specifically been proven necessary, it has served me well in similar situations.

Snails as a Calcium Source
Many arboreal geckos, Cyrtodactylus included, relish snails, and these seem to be an important source of calcium in the wild.

You can use small garden or aquarium snails, or smaller individuals of those species typically sold for human consumption (i.e. the grapevine snail, Helix pomatia). All can be rather easily reared at home, with the aquatic species being, in general, more prolific.

If you would like to raise your own snails, I suggest the large freshwater snails commonly sold as apple snails in pet stores. They are quite interesting in their own right, so don’t be surprised if you wind up paying them quite a bit of attention! Apple snails lay orange egg cases just above the water line; these are produced year-round, with more being laid as food intake increases. Apple snails feed ravenously, and do well on a diet of Spirulina disks and kale, romaine and other greens. They should also be provided with a piece of cuttlebone  (discard the metal holder provided for use with cage birds) as a calcium source. The young fall into the water upon hatching and grow rapidly.

Any of the small aquatic snails commonly found among aquarium plants can be bred and used as a food source as well.

Most terrestrial snails do not breed quite as rapidly as do apple snails, and temperate species need a cool period (a refrigerator works well) of 2-4 weeks at 38-40 F if they are to reproduce. Most feed readily upon tropical fish flakes, fruit, vegetables and cuttlebone.

Diet
Roaches stimulate most geckos to feed; many also respond with enthusiasm to moths, beetles and other wild caught insects. Please see my article on Raising Orange-Spotted Roaches  for more information.

I believe it to be very important to offer a variety of invertebrates to bent-toed geckos. If at all possible, try to collect local insects…the Zoo Med Bug Napper is very useful to have on hand.

Leave food in the terrarium overnight, and offer grubs, mealworms, wax worms and the like in cups suspended above ground as opposed to releasing them in the terrarium.

Further Reading
Providing reptiles with a varied diet is always important, but never more so than when dealing with bent-toed geckos and other little-studied species. Please see my article Collecting Live food for Reptiles and Amphibians for some tips on providing your lizard with wild-caught invertebrates.

Image referenced from Wikipedia and originally posted by W.A. Djatmiko. Image is NOT the Giant Bent-toed Gecko, but a related species, Cyrtodactylus marmoratus.

A Control Program Backfires
Please see Part I of this article for background information. With introduced green iguanas (Iguana iguana) driving endangered burrowing owls from their nests and raccoons (Procyon lotor) devouring sea turtle eggs, the Florida Department of Environmental Protection initiated control measures. At a preserve in Dania Beach, an intensive trapping and collection campaign greatly reduced the numbers of both species, but an unexpected consequence of these efforts soon became apparent.Within a year of the raccoon numbers being brought under control, iguana populations skyrocketed. In one area of the park, researchers counted 626 iguanas per square kilometer (0.4 square miles)…an unprecedented density for any lizard species!

It seemed that raccoon predation had been a very effective control on iguana numbers. Although hawks, gray foxes, night herons, alligators and other animals prey upon iguanas, only raccoons take eggs, hatchlings and sub-adults in significant numbers.

Iguanas…Here to Stay?
Young iguanas are now especially common at the site, pointing towards an even greater population increase in the future. Hand-collection, although possible, is a daunting task, so biologists are looking into alternate control measures. Meanwhile, spurred by ample food and little competition, lizards as young as 2 years of age are laying eggs.

In Belize, black rats effectively control one green iguana population by taking nearly every egg laid. However, Florida’s parks already have enough problems without black rats…in fact, their notorious cousin, the Norway rat, is already a resident of many!

Further Reading
It was my good fortune to work with green iguanas in a natural, if somewhat unusual (i.e. treeless) habitat. Please see my article, The Green Iguana on the Venezuelan Llanos  for the story.

To learn more about the challenges and rewards of keeping these impressive lizards, please check out our care guide, Green Iguanas.