Anole Lizard Care, Facts & Behavior

Allison's Anole

Uploaded to Wikipedia Commons by Fil.Al

In terms of the sheer number of species and of individual animals, Anoles may be the most successful of all lizard groups.  Each year, herpetologists add several new discoveries to the total species count – which now stands at 388!  In Anole-rich regions, several seemingly-similar species manage to co-exist in the same habitat…and many thrive in and around towns, farms and even cities.  Their adaptability sometimes leads to staggering population densities, with up to 10,000 Anoles per acre being present on some Caribbean islands!  Intelligence may also play a role in their success, as is shown by this fascinating study .  Many herpers of my generation were introduced to reptile-keeping by the Green Anole, Anolis carolinensis…today we’ll take a look at the fascinating, diverse family to which it belongs.

 

Classification

The world’s 388 Anole species are classified in the family Dactylidae (formerly Iguanidae) and the genus Anolis. 

 

Description

Most Anoles are alert and active, and nearly all have a streamlined body with long tails, limbs and digits.  Males have colorful dewlaps (areas of loose skin below the throat) that are erected during mating and territorial displays. Female Green Anoles, and those of several other species, sport smaller, less colorful dewlaps.  The body color is usually some shade of green, tan or brown, and many are capable of rapid color changes.

 

Leopard Anoles breeding

Uploaded to Wikipedia Commons by Nathalie Colucci

Anoles range in size from the various Twig Anoles, which barely reach 3 inches in length, to Cuba’s Knight Anole, A. equestris, an 18-inch long hunter of treefrogs, lizards, small snakes, and nestling birds.  The Grenada Anole, A. richardi, is also sizable, sometimes exceeding 12 inches in length.  Most Anoles, however, measure 6-8 inches when fully-grown.

 

Range and Habitat

Anoles range from the southern United States through the Caribbean and Mexico to Central and South America.  Mexico is home to over 50 species, while well over 100 occupy various Caribbean islands.  The USA has but a single native, the Green Anole.  However, it is by no means “Anole-poor”, as stowaways and released/escaped pets have resulted in the establishment of breeding populations of at least 9 foreign species!

 

In the USA, all introduced species except the Brown Anole are restricted to Florida, which is now home to Hispaniolan Green, Puerto Rican Crested, Barbados, Marie Gallant Sail-Tailed, Cuban Green, Jamaican Giant, Large-Headed, Bark, and Knight Anoles.  The highly adaptable Brown Anole has managed to extend its range into southern and perhaps central Georgia.  First documented in peninsular Florida in the 1940’s (and likely established earlier in the Florida Keys), the USA’s Brown Anole population is comprised of 2 interbreeding subspecies – the Cuban Brown Anole, Anolis sagrei sagrei and the Bahaman Brown Anole, A. s. ordinatus.

 

Anolis barbatus

Uploaded to Wikipedia Commons by Olaf Leillinger

While ground-dwellers are known, most Anoles are arboreal, with different species (often in the same habitat) favoring reeds, bushes, tree trunks, low limbs, and forest canopies.  Anoles have adapted to life in rainforests, dry forests, cities, farms, suburban yards, arid scrub, swamps, brushy grasslands, riverside thickets, and many other environments.  Some, such as the Cuban Brown Anole, may actually be more common around human dwellings than in their natural habitats.  This highly adaptable lizard has actually been observed to quickly change to an arboreal lifestyle after the introduction of a terrestrial predator (please see this article); many believe that it is also responsible for decline in Florida’s Green Anole population.

 

Anole Care and Feeding

Anoles make wonderful pets, as they are out and about by day, and usually quite active; their group dynamics will keep even the most experienced keeper fascinated.  Many breed year-round if properly cared for, and some may be housed with certain treefrogs, skinks and other animals.  However, the common opinion that Anoles are a “beginner’s” lizard does these fascinating creatures a great disservice.  All Anoles are highly-complex, and have very specific needs that must be met.  Without ample space and cover, proper temperatures, access to UVB and a highly-varied diet, they will not thrive.  Please see the linked articles for detailed information on their care, and be sure to post your questions and observations below.

 

t260596Anoles feed largely upon flies, caterpillars, spiders, beetles and other invertebrates, and many also take over-ripe fruit, nectar and sap.  Larger species, such as the Grenada and Knight Anoles, occasionally add smaller lizards, frogs and snakes to the menu.

 

Anoles are major food items for predators ranging from large spiders to small mammals and birds.  Therefore, most are instinctively wary, and they tend to remain high strung in captivity. While there are exceptions, few take well to handling.

 

 

Further Reading

How to Breed Green Anoles

 

Green Anole Natural History

 

Keeping Cuban and Hispaniolan Green Anoles

Nile Crocodile Found in Florida: Is World’s Largest Crocodile a Resident?

Nile Crocodile

Uploaded to Wikipedia commons by Tim Muttoo

Yet another Floridian reptile drama has made headlines.  Earlier this month (March, 2014) officials from the Florida Fish and Wildlife Commission (FFW) reported that a Nile Crocodile (Crocodylus niloticus) had been captured in the northwestern Everglades.  Although the origin of this particular animal may be known, it is not the first Nile Crocodile to have been captured in the state, which is now home to an astonishing 500+ species of non-native animals (and a great many plants)!  And while Nile Crocodiles are a rarity in Florida, the possibility of hybridization with the native American Crocodile (C. acutus) may be a concern.  In the course of my work in zoos and via contacts with commercial croc farming projects, I’ve seen many examples of hybrid crocodiles.  I cared for a Cuban Crocodile x American Crocodile cross, and Siamese Crocodiles are regularly interbred with others on farms.  Hybrid crocs were even openly offered for sale as “pets” back in the “Wild West” days of the pet trade (and perhaps still are?).

 

Nile Crocodile Origins

The recently-captured Nile Crocodile measured 5 ½ feet in length and weighed 37 pounds – too small to have reached sexual maturity (another, also an escaped exhibit animal, measured 9 feet in length when re-captured). It is believed to be the same individual that has been sighted several times over past 2 years.  FFW officials are looking into the possibility that this animal escaped from a Miami facility just before the sightings began.  If genetic evidence confirms

Ameriocan Crocodile

Uploaded to Wikipedia Commons by Mattstone911

this, the owners could be subject to a fine and/or imprisonment under Florida law.

 

Crocodiles and the Leather Trade

There has been speculation that live crocodiles imported to the USA for use in the skin trade may be another source of escapees.  However, all operations that utilize Nile Crocodiles are, according to the IUCN’s latest report, located in Africa (please see article linked below).

 

Nile Crocodiles are second only to American Alligators in terms of the number of skins sold each year.  The IUCN reports that between 2006 -2008, 1.5 million crocodile, alligator and caiman skins were legally traded.  Thirty countries and 13 crocodilian species were involved.  The global economic downturn has suppressed demand since that time.

 

Financial Concerns

Florida has the dubious honor of hosting more non-native invertebrates, fishes, reptiles, amphibians, birds and mammals than anywhere else on earth.  An astonishing 500+ exotic species have been observed, and many if not most have established breeding populations.  Last year, the federal and Florida state governments spent 80 million dollars in eradication attempts.  Threats to agriculture and habitats posed by introduced plants are also significant.

 

Other costs are involved as well – over the past decade, for example, 100 million dollars has been spent on re-establishing the endangered Wood Stork.  Nile Crocodiles and Burmese and African Rock Pythons are capable of preying upon Wood Storks, and other species could impact these endangered birds in ways that have not yet been identified.

 

Mexican Spinytail Iguana

Uploaded to Wikipedia Commons by John J. Mosesso, NBII

Notable Exotics: Reptiles and Mammals

Many of Florida’s introduced reptiles are very well-known, even to those without much interest in animals.  In some areas, Green Iguana populations are denser than in natural habitats…denser, in fact, than populations of any other lizard, anywhere on earth (please see article below for an interesting study on iguana-raccoon interactions)!  Brown Anoles seem to have replaced the native Green Anole in many areas, and 6-8 other anole species are established as well.  And, of course, one cannot escape news of introduced Burmese and African Rock Pythons and Boa Constrictors.

 

Less well-known is the fact that Spectacled Caimans (Caiman crocodylus) have been breeding in Florida since the 1960’s, which was their heyday in the pet trade.  Other surprising transplants include Javan File Snakes (Acrochordus javanicus), Texas Horned Lizards (Phrynosoma cornutum), Mexican and Black Spinytail Iguanas (Ctenosaura pectinata and similis) and Indochinese Tree Agamas (Calotes mystaceus).  There are many others…please post below if you wish a complete list.

 

I’m surprised that, with the exception of Armadillos and Nutrias, Florida’s introduced mammals do not seem to generate much interest.  The list really is quite amazing, and includes such large and unusual creatures as Asian Sambar Deer, American Elk, Jamaican Fruit Bats, Capybara, Mexican Red-Bellied Squirrels and Rhesus, Squirrel and Vervet Monkeys.  Please post below for more info, and see the linked article on Florida’s many feral parrots.

Sambar Deer

Uploaded to Wikipedia Commons by N. A. Naseer

 

Extermination efforts have rarely been successful, regardless of the species involved.  In fact, the FFW has given indications that the Burmese Python campaign may shift from “eliminate” to “control” mode.  I’ll post updates as they become available.

 

 

 

Further Reading

Raccoons and Iguanas in Florida – an Interesting Dilemma

 

Florida’s Introduced Parrots

 

Commercial Crocodile Farming (IUCN report)

My Leopard Gecko Is Not Eating: What To Do

 

 

Adult female

Uploaded to Wikipedia Commons by Jerome66

When cared for properly, Leopard Geckos are among the most hardy and long-lived of all reptile pets.  But apparently-healthy geckos sometimes refuse to feed, or cut back on their intake, and there is still much confusion as to why this occurs.  My work with Leopard Geckos and hundreds of other species in zoos and at home has (I hope!) provided me with some useful insights into this problem.  Some involve areas that any good reptile keeper would investigate – environment, stress levels, disease – while others, such as the effects of circadian rhythms (“internal clocks”), are less obvious.

 

Winter’s Arrival and Internal Rhythms Regulate Eating

Leopard Geckos are native to southeastern Afghanistan, western India, Pakistan, Iraq, and Iran, where they inhabit desert fringes and arid grasslands.  In some parts of this range, temperatures rise to 100+ F in summer and drop below 32 F during the winter.  Wild Leopard Geckos living in environments that experience severe winters become dormant for several months each year, while those in milder regions may remain active (please see the article linked below to read more about their natural history).

 

While your pet is, no doubt, many generations removed from the wild, internal circadian rhythms may cause it to become lethargic and refuse food during the winter.  This can happen even if your gecko is kept warm and given a photo-period of 12-14 hours.  To confuse matters further, some reptiles enter dormancy when winter arrives in their native habitats…even if it happens to be summertime in their present home!  I’ve seen this among Indian Gharials (fish-eating crocodiles) 15 years removed from the wild, and in many others.  Captive Bearded Dragons also exhibit this type of behavior on occasion; please see this article.

 

leopard geckoUnfortunately, it’s not often possible to be certain that a pet has stopped feeding due to the effects of an internal rhythm, so be sure to check the other possibilities discussed below.

 

Next I’ll mention other things that should be checked if your gecko stops feeding, including husbandry (tank set-up, temperatures, diet, etc.), stress, and disease.  I’ve written on each of these in further detail in the linked articles.

 

Your Gecko’s Environment

As Leopard Geckos are nocturnal, it’s important to monitor nighttime temperatures, especially during the winter, when most people lower their home thermostats.  The ambient air temperature should range from 78-84 F, which can be maintained by a ceramic heater or red/black reptile “night bulb”; a below-tank heat mat should be positioned so that one corner of the tank is warmer (88 F) than the rest.  Be sure also to establish a thermal gradient (areas of different temperatures) so that your gecko can regulate its body temperature as needed.

 

tPG01794While Leopard Geckos often adapt to smaller enclosures than do other lizards, individuals vary in their response to crowding.  Moving your pet to a larger terrarium may help, and this will also make it easier for you to establish a thermal gradient (small terrariums tend to remain at the temperature of the basking site).

 

And, no matter how well-adjusted or bold your pet may be, it’s important to provide a dark, secure cave or other shelter.  Geckos forced to remain exposed often cease feeding.

 

Diet

Wild Leopard Geckos feed upon a huge array of invertebrates, while pets are often limited to 2-3 food items.  Dietary variety is important for health reasons.  But providing different types of insects can also incite new interest in feeding.  We see this most commonly in chameleons, but the enthusiasm your Leopard Geckos will show for novel foods will leave you with no doubt as to their value.  Please see this article to read more about adding silkworms, house flies, sow bugs, wild-caught insects and other important foods to your pet’s diet.

 

Stress Can Affect Eating

Geckos may be stressed by the mere presence of a dominant cage-mate, even absent fighting.  If you suspect aggression, observe your geckos after dark, when they will be most active (a red/black reptile bulb will prove useful).  Appetite-suppressing aggression is especially common among young geckos that are being raised in groups.

 

Locating the terrarium in a noisy part of the house, or where there are vibrations from machinery, may also depress appetites and contribute to other health concerns.

 

Disease and other Health Issues

Impactions from substrate swallowed with meals and Metabolic Bone Disease are two of the more common reasons that geckos cease feeding.

 

Other health concerns that have been identified include Hyperthyroidism, Eyelid Lining Retention (following shedding) and Cryptosporidiosis.  Internal or external parasites, and a host of other less common ailments, should also be investigated if your pet stops eating.  Please post below if you need help in locating a reptile experienced veterinarian.

 

 

Further Reading

The Leopard Gecko in the Wild

 

The Ideal Leopard Gecko Terrarium 

 

Guam Brown Tree Snake Eradication: Bad News for People & Wildlife

Threat display

Uploaded to Wikipedia Commons by Soulgany101

As a Bronx Zoo animal-keeper in the early 1980’s, I became involved in a breeding program for Guam Rails and Micronesian Kingfishers. Both birds were facing extinction due to a most unusual threat – the introduced Brown Tree Snake, Boiga irregularis.  Back then, major problems caused by trans-located snakes were unknown.  Although Burmese Pythons had been established in Florida since the early 70’s, these now-famous invaders had not yet grabbed the public’s attention.  A zoologist friend journeyed to Guam to investigate, and he was soon regaling me with fantastic stories.  In keeping with its species name, this snake was most “irregular” – biting at the moving eyelids of sleeping children, stealing burgers from grills, and often being found in bird cages – too engorged to slip back out after having swallowed the family pet!  Today, the rail and kingfisher are gone from Guam, and other birds, lizards and bats have become extinct.  Yet the Brown Tree Snake has not, as was predicted, eaten itself into oblivion.  Huge populations – to 13,000 snakes per square mile – are sustained by other prolific invaders, one of which is the Green Anole!

 

The Brown Tree Snake’s History on Guam

Flowerpot Snake

Uploaded to Wikipedia Commons by Hinrich Kaiser and Mark O’Shea

Although many accounts describe Guam as “snake-less” prior to the Brown Tree Snake’s arrival, the island does have one native species, the tiny Brahminy Blind or “Flower Pot” Snake, Rhamphotyphlops braminus (please see photo)Able to reproduce by parthenogenesis, it is a common stowaway in plant shipments.  Feral populations exist in many places, including (of course!) Florida.

 

The Brown Tree Snake most likely arrived on Guam during World War II, secreted in crates sent there from US military bases on the Admiralty Islands.  Huge populations of native lizards and birds that had evolved without snake predators allowed it to explode in numbers.  The snake began gaining attention in the 1950’s, and occupied the entire island by 1968.  The invasion gained widespread notice in the early 1980’s, due to massive declines in bird populations and increased human-snake encounters.

 

Description

The Brown Tree Snake is a rear-fanged species that averages 3-6 feet in length, but those living on Guam sometimes approach 11 feet.  Guam specimens range from olive-green to dark tan in color, and are marked with darker blotches.  Other populations are colored brown, greenish-tan or beige with rusty-red markings.

 

Their venom has not caused human fatalities but is a concern for certain individuals (please see below).  Prey may be partially immobilized by the snake’s body, but they are not constrictors in the true sense of the word.

 

The individuals that my friend brought back from Guam were among the most aggressive snakes I’ve seen.  Bold and high-strung, Brown Tree Snakes bite many people on Guam.

 

Range and Habitat

The Brown Tree Snake’s natural range stretches from the northern and eastern coastlines of Australia to New Guinea, the Solomons, Sulawesi and many neighboring islands.

 

Guam Rail

Uploaded to Wikipedia Commons by Greg Hume

Less well-known than Guam are the many other locales to which the Brown Tree Snake has been transported.  The most far-flung is Corpus Christi, Texas, where one was found after a 7 month journey in a crate shipped from Guam.

 

It is not known if this world traveler has established breeding populations elsewhere, but it has been collected on Hawaii, Saipan, Okinawa, Wake, Taiwan, the Cocos, Rota and many small Micronesian islands. Anecdotal reports suggest that it has appeared in airports in Japan, Spain and Singapore.

 

Common name notwithstanding, the Brown Tree Snake adapts well to brushy scrub and relatively treeless habitats.  It readily colonizes villages, farms and cut-over woodlots.

 

Brown Tree Snake’s Effect on Guam’s Wildlife

Lizards

Although best known for annihilating Guam’s birds, the Brown Tree Snake has had a significant impact on most native vertebrates. Six of the island’s 12 lizards have now disappeared.  Several, such as the Azure-Tailed Skink, Emoia cyanura and the Moth Skink, Lipinia noctura, are poorly studied and may be in trouble elsewhere as well.

 

Three fast-breeding introduced lizards, the Green Anole, Anolis carolinensis, the House Gecko, Hemidactylus frenata, and the Curious Brown Skink, Carlia fusca, seem responsible for the continued success of the Brown Tree Snake on Guam. They now make up most of the snake’s diet, but remain common.

 

The Mangrove Monitor, Varanus indicus, is also in decline, but this may be due to yet another introduced herp – the Marine Toad, Bufo marinus.  Monitors that eat toads are killed by its virulent toxins.   It is not known whether the Mangrove Monitor is native or was introduced to control rats (it seems better at controlling chickens and their eggs than rats!).

 

Mammals

Guam was home to only three native mammals, all bats.  Two have been extirpated by the snake, and the Marianas Fruit Bat is now limited to a single small colony.

 

Micronesian Kingfisher

Uploaded to Wikipedia Commons by Dylan Kesler

Birds

The birds with which I worked years ago, the Micronesian Kingfisher and the Guam Rail, are now well-established in zoos.  However, as Guam is their sole habitat, they are extinct in the wild.

 

The Brown Tree Snake has also eliminated all of Guam’s nesting seabird colonies (White-Tailed Tropicbird, White Tern, Brown Noody) and 10 of its 13 forest-dwelling birds. Micronesian Starlings survive by nesting in cities, and some Marianas Crow nests are protected by electric barriers – but fruit doves, honeyeaters and others have vanished.

 

Effects on People

The Brown Tree Snake has impacted Guam’s people and economy in a manner unprecedented for a reptile.  Examples include:

 

Bites, especially to sleeping children, are very common.  Small children may exhibit signs of envenomation, and in some cases must be treated for respiratory distress.  Allergic, elderly, and immune-compromised individuals are also at risk.  The fear and trauma factor is also quite high.

 

Power outages caused by electrocuted snakes cost up to 4 million dollars yearly.

 

Property values and tourism have declined, with people and businesses relocating.

 

Guam’s air cargo industry has suffered due to the lengthy examinations required.

 

Lizard and bird extinctions may have led to recent mosquito-borne dengue fever and Salmonellosis outbreaks and to a sharp decline in farming due to insect predation on crops.

 

The poultry industry has been decimated; most eggs now imported.

 

Brown Tree Snake Eradication Attempts

In addition to vanquishing many native species, the Brown Tree Snake is besting its human enemies as well.

 

The most controversial attack method is airplane-drops of mice laced with Paracetamol, a snake-toxic pain killer. The mice are attached to tiny cardboard parachutes (who makes these?!) designed to keep the bait in trees and away from children and domestic animals.  The “tiny assassins” program costs the US government an estimated $8,000,000 annually.

 

Trapping has proven to be the most effective control technique, but success hinges on using many traps.  As the modified minnow traps are baited with live geckos and mice, maintenance is very labor intensive.

 

Snake-detecting dogs, debris and scrub-growth removal, and snake barriers are also used with varying degrees of success.

 

Research

Research is being conducted by many organizations, including the US Geological Survey, Princeton University and the National Zoological Society.  Manipulation of breeding biology, snake diseases and parasites, poisons, and heat-fumigation treatments for cargo areas are being explored as control measures.

 

 

Further Reading

Toxic Mice Dropped Over Guam

 

Red Eared Sliders Out-Compete Native European Turtles

 

New Species of Sailfin Dragon Found During Pet Market Study

Philippine Sailfin Lizard

Uploaded to Wikipedia Commons by MKFI

The three species in the genus Hydrosaurus, commonly referred to as Sailfin Dragons, are among the most spectacular lizards on earth.  Even after decades of working with all manner of reptiles in zoos and the field, I’m still stopped in my tracks by the sight of one.  Unfortunately, the coastal swamps and forests they inhabit are being developed out of existence, and captive breeding is not common.  Recently, genetic studies of lizards illegally held in Philippine pet markets surprised herpetologists by bringing to light a new species of Sailfin Lizard.

 

The Currently-Recognized Species of Sailfin Dragons

The Philippine Sailfin Lizard, Hydrosaurus pustulatus, is the species most commonly seen in the pet trade.  Stoutly built and reaching over 3 feet in length, males sport huge crests along the back and tail, and are clad in several shades of green, neon purple, and red-tinted blue.  Small wonder they are high on the wish-lists of lizard enthusiasts worldwide (and “large wonder”, in my opinion, why zoos do not pay them more heed!).

 

The Amboina Sailfin, H. amboinensis, is found in Indonesia and New Guinea; its occurrence in the Philippines is debated.  Weber’s Sailfin Lizard, H. weberi, appears limited to the Indonesian islands of Ternate and Halmahera.

 

Unfortunately, Sailfin Lizards are a poor choice for all but experienced keepers with a great deal of space.  They require huge enclosures and usually remain high-strung, even after years in captivity. Today, as in years past, nearly all in the trade are wild-caught, and captive breeding is very rare.

 

Riverine rainforest

Uploaded to Wikipedia Commons by bri vos

An Uncertain Future for Sailfin Lizards

In order to access the Sailfin Lizards’ status and formulate a conservation strategy, herpetologists from the University of Oklahoma surveyed natural habitats and pet markets in the Philippines (Biological Conservation, V 169, Jan, 2014).  The coastal marshes and riverside forests upon which these lizards depend were found to be under immense pressure from logging, fishery expansion and other forms of development.  Only 10% of the Philippine Sailfin Lizard’s habitat lies in protected areas – the rest is open to human activities. The species is classified as Vulnerable by the IUCN.

 

Illegal collection also seems to be a problem, as black market animals were easy to locate, and field surveys of easily-accessible habitats revealed few adult specimens.

 

A New Species Emerges

Animal markets in Manila seem to be the main source of entry into the pet trade.  DNA studies of scale and nail-clippings from lizards found in these markets revealed that Sailfins inhabiting Sulawesi, Indonesia are genetically distinct from those in New Guinea; both are now classified as H. pustulatus.  The newly-described species has not yet been named.

 

Why Bother with Genetic Identification?

“Discovering” new species via genetic research is becoming ever more common, and I think there’s sometimes a tendency to regard this as less noteworthy than finding an animal that is “new” in the sense of having never been seen, or seen only by people living within its habitat.

 

However, it’s important to bear in mind that genetic differences evolved over millions of years undoubtedly have survival value.  Well-known examples abound – Green Anoles from southern Florida cannot tolerate north Florida winters, venoms of rattlesnakes with wide ranges differ radically (in response to prey defenses) from place to place, and so on.  These unnoticed but very significant differences can greatly affect conservation plans and captive breeding attempts.

 

Also, properly identifying a species can have important implications where legal protection is concerned.  Considering the horrific confusion and red tape that plagues international conservation laws, any means of introducing order and clarity should be welcomed.

 

Green Basilisk

Uploaded to Wikipedia Commons by Joseph C Boone

A Sailfin Dragon “Substitute” for Lizard Fans

As mentioned earlier, Sailfin Lizard ownership should not be undertaken lightly, as they are quite demanding pets.  However, those who are enamored of large, beautifully-colored lizards bearing “dragon-like” crests do have excellent alternatives – the Green Basilisk, Basiliscus plumifrons and the Asian Water Dragon, Physignathus cocincinus.  You can read more about the care and breeding of these very impressive lizards in the articles linked below.

 

 

Further Reading

Breeding the Green Basilisk and its Relatives

Keeping the Asian Water Dragon

Scroll To Top