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

I grew up “knowing” green iguanas to be largely arboreal lizards of thickly-forested habitats.  In time, I was able to confirm that impression by observing them high in the canopy of a Costa Rican rainforest, and in the tall trees of Tortuguero Island, Costa Rica…where, in accordance with what I had read, they dove into the river when disturbed.

So I was quite surprised, upon arriving in Venezuela’s flat, largely treeless llanos, to find these flooded grasslands well-stocked with the huge lizards.  I was there to study green anacondas (also a surprising find, given my past impressions, but we eventually tagged over 500) but found it impossible to limit my attention to them, so overwhelming was the diversity of wildlife.

The green iguanas grazed on the flat, treeless terrain like so many cows…in fact, they were often among cows, as much of our work was on a cattle ranch.  When threatened (i.e. by me trying to catch one), they took off at incredible speeds and dove into the water.

One stout brute of 5’11” in length (please see photo showing side-view) absolutely refused to enter the water when he reached its edge.  He held his ground, thrashing his tail (please see photo showing cut left on my arm by a smaller animal’s tail) and lunging at me.  Once subdued, I was able to see that he had numerous old wounds that had likely been inflicted by piranhas, and was missing several toes.  Perhaps his stretch of the river had a particularly aggressive piranha population, and he preferred a battle on land to another swim!

I’ve included a photo of typical iguana habitat in Venezuela’s central llanos country, to perhaps show you why I was so surprised to find the lizards there (the creatures in the foreground are capybaras, world’s largest rodent).  Also included is a photo of another reason that an iguana might choose to run or fight rather than swim – a huge green anaconda basking at the surface.

Today we can see ample evidence of the green iguanas’ adaptability right here in the USA – feral animals live in areas ranging from beaches to suburban gardens throughout south Florida!

Detailed information on green iguana behavior and typical habitats is posted by the Green Iguana Society at:

http://www.greenigsociety.org/inthewild.htm

An article published in the June 30, 2008 issue of The Proceedings of the National Academy of Sciences documents a heretofore unknown vertebrate life-history strategy…2/3 of the Labord’s chameleon’s life is spent within the egg.

Native to southwestern Madagascar, this tiny lizard lives for only 4-5 months, after an incubation period of 7-9 months.  The entire life cycle is synchronized to an extraordinary degree, with nearly all members of the species hatching, breeding and dying in concert.  Uniquely for a lizard, no adults survive until the next generation hatches…all individuals hatch in November, mate in January, and die shortly thereafter.  The time period from conception to death – usually less than 1 year – is perhaps the shortest known for any vertebrate.

Researchers are trying to identify the genetic or hormonal process that regulates the lifespan.  An understanding of this phenomenon may point to ways of controlling cell death in humans.

You can read about field research projects dealing with this and related chameleons at:

http://www.madagasikara-voakajy.org/en/reptiles_and_amphibians

Click: The Green Anole (Anolis carolinensis carolinensis) in the Wild and Captivity – Care in Captivity Part I, to read the first part of this article.

Light, Heat and Humidity
Green anoles rarely live for long if maintained without full spectrum lighting. If a florescent bulb is used, be sure that all animals can bask within 12 inches of it (within 20 inches of the Zoo Med 10.0 UVB Bulb). These lizards are completely diurnal and most active in bright sun, and UVA and UVB are essential if they are to thrive and reproduce. Horizontal and diagonal branches are preferred over vertical perches as basking sites.

Zoo Med’s High Output 10.0 Florescent Bulb is a fine source of UVB light for green anoles. The Zoo Med Reptile Halogen Bulb is ideal for providing UVA, along with heat for the basking site. For larger cages, a Mercury Vapor Bulb will supply UVB over a greater distance than will a florescent bulb.

The ambient air temperature should be 84-87 F, with a basking spot of
92-95 F. Over-night temperatures can dip to the low-mid 70’s, assuming the animals are in good health (use a ceramic heater or Reptile Nightlight Bulb if supplementary nighttime heating is required).

Green anoles prefer moderate to high humidity levels, but need to bask and dry out as well. The terrarium should be misted twice daily, more often if needed to combat the drying influence of incandescent bulbs. A screen top should be used to ensure adequate air circulation.

Feeding
Crickets and Commercially Available Insects
A “cricket only” diet, while convenient, should be avoided. I have found that a varied diet is vital for long-term maintenance of green anoles. When using crickets, be sure to select only half-grown or smaller animals for adult anoles, as they are prone to blockages when fed adult crickets. The crickets should themselves be well fed before being offered to your pets.

Small roaches, waxworms, butterworms and mealworm beetles should also be provided. Anoles are often reluctant to come to the ground to feed, so provide these insects in a cup suspended among the branches. Pinch off several legs of the roaches in order to keep them confined – being nocturnal, they will likely escape notice if released into the terrarium. Only small, newly molted (white in color) mealworms should be fed to green anoles, and these not more than once monthly.

Wild Caught Insects – the most important part of the diet
Wild caught insects (i.e. collected via Zoo Med’s Bug Napper) should be provided often. Anoles under my care have been particularly fond of moths, flies, tree crickets, hairless caterpillars, harvestmen (“daddy longlegs”) and small spiders. During the warmer months of the year, I collect nearly all of the invertebrates that I give to insectivorous reptiles, but even an occasional wild-caught insect will be of great value to your pet. The Bug Napper is indispensible in this regard. Small silkworms and house flies should be ordered from insect suppliers periodically.

Canned Insects
In order to increase dietary variety, anoles should be acclimated to tong feeding and offered canned grasshoppers, silkworms and other commercially-available insects.

Nectar and Water
Wild anoles of various species have been observed lapping at sap and nectar, although in my experience not all green anoles do so in captivity. The following mixture, suspended in cups set among the branches, should be offered weekly:
1/3 jar papaya, apricot or mixed fruit baby food
1 teaspoon honey
¼ teaspoon liquid bird vitamins or powdered reptile vitamins
Water sufficient to achieve syrupy a consistency

Anoles will not drink water from bowls (some will if the water is kept in motion by an air stone); their enclosure should be misted twice daily.

Frequency of Feeding
Green anoles have fairly high metabolisms and do best on small frequent feedings – meals should be provided daily or every other day. This is especially important in group situations, where competition may limit feeding opportunities for some animals. The food of adults should be sprinkled with a reptile vitamin/mineral supplement twice weekly.

Green anoles are taken for granted – while not “easy”, they are manageable with a bit of effort, and may well turn out to be one of your most interesting lizard-keeping endeavors. I’ll continue with their captive care next time.

Please see Green Anole Natural History for information concerning the natural history of the green anole and its relatives.

General
Green anoles became a US pet trade staple in the 1960’s and early 70’s. Labeled “chameleons” due to their color-changing abilities, millions were collected in Florida and Louisiana and sold at circuses, fairs, pet stores and through the mail. In time, they became the “first lizard” for a generation of budding herpetologists. A host of grossly inappropriate supplies (including lapel chains!) and husbandry techniques assured most of the unfortunate creatures a short and unhappy captive existence.

My Less-Than-Promising Start
I remember well purchasing a green anole (packaged, oddly enough, in a small pie box) at the famous Ringling Brothers, Barnum and Bailey Circus at Madison Square Garden in the early 60’s. I knew enough to bypass the recommended diet of “sugar water and dried ant eggs” but was ignorant of the beast’s UVB requirements. I did, however, gather that it craved sunlight, and during one basking trip the lizard escaped up a caterpillar- laden apple tree where, I hope, it at least enjoyed the NYC spring and summer.

A Bit Delicate, but Well-Worth the Effort
Green anoles do reasonably well in captivity but are not the hardy, “starter lizards” they are often proclaimed to be. They are prone to stress-related ailments, require careful attention to the diet, and are quite sensitive to light, temperature and humidity levels.

That being said, I feel that their potential is largely ignored – a properly maintained group will readily display numerous social interactions, and makes as active and interesting a lizard exhibit as can be imagined. What’s more, establishing a colony of green anoles in such a situation is well within the financial and space constraints of many pet keepers, which cannot be said of most lizard species.

My co-workers at the Bronx Zoo frowned when I began adding green anoles to several large exhibits, but they (the lizards, not co-workers!) quickly became crowd pleasers. Even in an exhibit housing 2 huge water moccasins, it was the leaping, displaying anoles that drew most of the public’s attention.

Enclosure and Physical Environment
Green anoles are highly arboreal and will prefer the upper reaches of their enclosure. Branches of various thicknesses and orientations should be provided, along with plentiful sight barriers in the form of suspended live or artificial plants.

Despite their small size, green anoles require a good deal of room, as they are very active and are easily stressed by tight quarters or if confined too closely to one another. Ideally, a trio should be provided with a well-planted, 20 gallon aquarium.

Males are intolerant of each other. If several females are kept, horizontal and diagonally oriented basking sites (these are preferred over vertical branches) should be plentiful, as dominant animals will exclude others from these important areas.

Anoles do best in complex exhibits, especially those with live plants. They are quite easy on live plants, and really do look at their best when among them. Snake plants, pothos, Philodendron, peace lilies and many others will be well-used by these little gymnasts, and the areas between large leaves make naturalistic nocturnal retreats.

Arboreal shelters, in the form of cork bark and hanging plants, should be provided. These and similar sight barriers are important, as females will establish a dominance hierarchy, and subordinate animals may be inhibited from feeding or basking, even absent outright aggression.

The substrate should hold a bit of moisture but not be soggy. I recently used Exo-Terra Jungle Earth with a covering of Compressed Frog Moss and dead leaves in a public exhibit, and am pleased with the results. You can also use Keeper’s Choice Red Cypress, Exo-terra Forest Bark or Coconut Husk, with any type of moss mixed in.

Click here: The Green Anole (Anolis carolinensis carolinensis) in the Wild and Captivity – Care in Captivity Part 2, to read the rest of this article.

Click:The Green Anole (Anolis carolinensis carolinensis) in the Wild and Captivity; – Natural History – Part 1 to read the first part of this article.

Introduced Anoles
The green anole is the only anole native to the USA, but eight other species, originating as escaped or released pets, have established breeding populations here. The most common and widespread is the brown anole (A. sagrei), now found throughout Florida and in southern Georgia, Alabama, Louisiana, Texas and Hawaii. In many areas it is now more commonly encountered than the green anole.

The knight anole (A. equestris), bark anole (A. distichus), large-headed anole (A. cybotes), Hispaniolan anole (A. chlorocyanus), Cuban green anole (A. porcatus) and Jamaican giant anole (A. gormani) are limited to the vicinity of Miami and Miami-Dade County at this time.

Ill Fated Pets
Green anoles were sold by the millions at carnivals, circuses and through the mail in the 1960’s and early 70’s. Termed “chameleons” due to their color changing abilities, most were fed “sugar water” and expired in short order.

Color Change – not as obvious as it seems
Color change in the green anole has little to do with the background upon which the animal rests (although the colors it exhibits are usually cryptic). Cool or stressed anoles are brown in color, while warm, resting individuals are pale green and warm, active animals are bright green. Anoles involved in aggressive displays develop a black patch behind the eyes.

Unique Climbing Aids
Green anoles are assisted in climbing by transverse lamellae on the bottoms of the toes and feet. These thin structures are divided by thousands of grooves, and provide excellent traction against tiny irregularities in the surface upon which the lizard is moving. Utilizing the lamellae, anoles can even grip dirt particles lodged on glass, and hence climb window panes and aquarium sides easily.

Cold Tolerance and its Conservation Implications
Research has demonstrated that anoles from south Florida lack the cold tolerance exhibited by those in north Florida, and could not survive the winters there. Information such as this is vital in planning reintroduction and captive breeding programs for animals with large ranges. Inter-breeding animals that originate in widely different parts of their range can have disastrous consequences, despite the fact that they are of the same species.

In one case, ibex (mountain dwelling goats) from several European countries were released in the Pyrenees Mountains, to bolster the local population. The animals reproduced, but the offspring resulting from the crossing of native and non-native ibex were genetically programmed to give birth in mid-winter, and the population eventually became extinct.

An interesting summary of research being conducted on free-living green anoles by students at UT Knoxville is posted at:
http://eeb.bio.utk.edu/echternacht.asp