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

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.

 

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.

 

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.

 

Anoles 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

 

 

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.

 

Unfortunately, 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.

 

While 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 

 

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.

 

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.

 

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

What DO Leopard Geckos Eat?! The Leopard Gecko, Eublepharis macularius, makes a wonderful pet for novices and advanced hobbyists alike (even after many years as a professional zookeeper, I enjoy keeping them, and wrote a book about their care).  However, both sellers and buyers sometimes underestimate this delightful lizard’s needs, especially where feeding is concerned.  Contrary to popular belief, vitamin-powdered crickets and mealworms do not constitute a suitable diet!  If you wish your pet to live out its potential lifespan of 20-30 years in excellent health, you’ll need to provide it with as many different foods as possible.  Fortunately, a surprising array of insects can be purchased online and in stores.  Collecting and rearing your own insects is another excellent way to add to your gecko’s quality of life…and its great fun as well! Read More »

 

My grandfather cautioned me never to bet on a boxing match, as they were even less predictable than horse races.  But where chameleon fights are concerned, it seems that picking a winner is a simple matter.  A recent study revealed that color intensity and the speed with which a male can elicit color changes accurately predicted the winner of an aggressive encounter.  Furthermore, different areas of the body are used to covey specific types of information.  Chameleons know this, of course…which is why most contests end without physical contact between competing males.

 

Camouflage, Display, or Both?

Years ago, chameleons were thought to change color primarily to camouflage themselves from predators and prey.  In time, we learned that temperature, health, stress levels, dominance and other factors also played a role.

 

In recent years, researchers at Melbourne University discovered that communication, not camouflage, was the driving force behind the evolution of chameleons’ amazing abilities.  However, their work revealed that camouflage is involved as well.  At least one species, Smith’s Dwarf Chameleon, Bradypodium taeniabronchum, changes color when a predator appears…and the degree of color change varies according to the type of predator it faces!  You can read more about both studies in the articles linked below.

 

Colors Convey Distinct Message

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Veiled Chameleons, Chamaeleo calyptratus  (which are unsociable even by chameleon standards!) were the subject of a recent study that examined color change and aggression (Biology Letters, 2013; 9 (6)).  Researchers at Arizona State University photographed and analyzed 28 distinct areas on the bodies of male chameleons involved in aggressive displays with rivals.  The brightness of the colors exhibited in certain body stripes foretold which of the chameleons would make the initial approach towards the other.  Head color intensity accurately predicted the contest’s winner.  The speed with which the various color changes took place also affected the fight’s outcome.

 

The vast majority of the staged aggressive encounters ended without physical combat. The rare battles that did occur lasted a mere 5-15 seconds.

 

Why Quit Before the Fight Begins?

I’ve read elsewhere that color change takes a heavy toll, metabolically, on a chameleon.  I imagine that a male who can quickly summon up a variety of bright, intense colors is viewed by rivals as being healthy and vigorous, and therefore not worth tackling.  Similar considerations may influence mate choice as well.

 

Seeing as a Chameleon Sees

Chameleons and many other creatures do not perceive colors as we do.  The Arizona State University study was the first to examine the effects of color change “through the eyes” of an animal.  Using a process that I did not completely (or, truthfully, even barely!) understand, specialized cameras and information concerning chameleon visual sensitivity allowed researchers to measure colors as they are actually seen by chameleons.

 

 

Further Reading

Chameleon Color Change: Advertising and Camouflage

 

Chameleon Basking Influenced by Vitamin D Levels in Blood

Veiled Chameleon Care