"The wide world is all about you:

you can fence yourselves in,

but you cannot for ever fence it out."

    Gildor Inglorion to Frodo Baggins, in The Lord of the Rings: The Fellowship of the Ring

    John Ronald Reuel Tolkien (1892-1973)

Saint Croix's ameiva, Ameiva polops, male. Protestant Cay, off northern Saint Croix, United States Virgin Islands.

Creatures of Enchantment

REPTILES

    The scaly ones: breathtaking theophanies of fulgent splendor.

    My favorite animals.

    Ancient reptiles, like their anapsid ancestors, were among the first amniotes and, as such, among the first truly terrestrial vertebrates in that they severed their reproductive ties to water.

    Until rather recently the term "reptile" had quite a specific "popular" definition that included just lizards, snakes, turtles, crocodiles, and tuataras. That has changed with the ever-increasing use of information on genetics and a better understanding of cladistics and phylogenies, coupled with the disuse of morphology to define species and lower taxa.

    According to the best (at present) cladistic definition, and without discussing the scientific terminology that describes common traits, a "reptile" is "the most common recent ancestor of extant turtles, crocodilians, and saurians, and all of their descendants". In other words, the diapsids. Thus, the group actually includes not only the aforementioned poikilothermic organisms popularly known as "reptiles", but also endotherms such as pterosaurs and dinosaurs (including the "avian dinosaurs" - birds).

    However, I will follow the traditional taxonomic usage of the term "reptile" to refer to turtles, crocodiles, lizards, snakes, and amphisbaenians, and will treat birds in their own sections.

    No other vertebrate group is as varied in this region as reptiles, and no other has as many endemics per island as it does. Hundreds of species live in the Caribbean, and even the smallest cays are inhabited by some reptiles, as long as they have some woody vegetation on them. In fact, although the number of genera is rather low if compared with that of the continental Neotropics, the reptilian fauna of the Antilles comprises more species (perhaps more than 500) than the sum total of all other terrestrial vertebrates in the region.

    The West Indies truly are islands of reptiles.

The Reptiles of the Caribbean Islands

    Due to their impermeable skins and capacity for fasting during long periods of time, many of these reptiles are able transoceanic colonizers of new regions. In the New World, and in modern times, several species of Hemidactylus geckoes have invaded both insular and continental areas by hitch-hiking on man's ships. Even earlier, some species of the same genus evolved in the Antilles and South America after their ancestors crossed the Atlantic Ocean on rafts of fallen trees and branches, all the way from distant Africa. Among the West Indies themselves, interesting biogeographic patterns arise when species of one island invade, and sometimes further speciate in, other islands found quite some distance away. For example, the Cuban Anolis porcatus invaded some of the Bahamas and Navassa Island (off western Hispaniola) and continental North America, where it evolved into local endemic species. The Hispaniolan Anolis distichus have also invaded the Bahamas and North America, evolving into at least endemic subspecies there. And the blind snake Typhlops platycephalus and the anole Anolis cristatellus, both Puerto Rican, have naturally invaded some of the Bahamas. The latter evolved there into Anolis scriptus.

    Some Antillean genera are widespread, and two reign supreme by the sheer number of their species: Anolis (anoles) and Sphaerodactylus (dwarf geckoes). Anoles and dwarf geckoes are everywhere in the Caribbean islands: in deserts, rain forests, coastal thickets, pine woodlands, grasslands, swamps, and from sea level to the cold summits of the high mountains. In fact, Anolis is the largest known genus of reptiles, with about 400 species described to date. Probably many more remain to be discovered in both genera and, while they are also found in the American continents, it is in the West Indies where they reach unparalleled degrees of diversity and ecological adaptation.

ORDER SQUAMATA: LIZARDS AND SNAKES

    Lizards and snakes (order Squamata) are the largest extant group of reptiles. They inhabit every continent except Antarctica, as well as many islands continental and oceanic. A few Eurasian species are found even within the Arctic Circle.

    For the sake of an orderly discussion, I will treat lizards apart from snakes, but it must be understood that there is not a clear phylogenetic separation between the two groups.

SUBORDER LACERTILIA: LIZARDS

    Most species of lizards are diurnal, although many are primarily nocturnal, particularly among geckoes (Gekkonidae) and night lizards (Xantusiidae). They range in size from the minute Jaragua sphaero (Sphaerodactylus ariasae), to the three meter-long Komodo monitor, (Varanus komodoensis), of Indonesia.

    Highly adaptable, lizards have invaded almost every niche on Earth, and can be found everywhere from deserts to rain forests, on the ground, underground, and on trees, and just below the snow line of alpine regions. Most species have strong legs, and some can run very fast, indeed. Others have vestigial limbs or have lost them altogether, their resulting morphologies and means of locomotion being serpentine. A number of them are semi-aquatic in freshwater and marine habitats, although no modern species have severed their ties to land completely (the gigantic mosasaurs, extinct relations of the modern monitors, were truly marine). By far, most species reproduce by eggs, although some are ovoviviparous.

    Unlike several groups of snakes, lizards have not developed poison glands and means to inject venom into their prey. None, that is, except for the helodermatids of North America. However, it has been recently discovered that just because most lizards - and, for that matter, most snakes - do not possess a specialized mechanism to inject venom, it seems that many, if not most, possess virulent enzymes in their saliva that can be moderately to deadly toxic to the habitual prey. It has been know for some time that the earless monitor of Borneo, and a few species of Varanus monitors, all in the Old World, have toxins in their saliva. But it might sound strange, but nonetheless be true, that a "cute and harmless" lizard like an anole or curlytail can be deadly venomous... just not to humans. After all, many toxins are highly specific in their targets, and anoles do not habitually hunt and devour people.

    Diurnal lizards frequently possess excellent color vision, indeed probably better than ours. The gaudy colors of many iguanids, agamids, and chameleonids serve as inter- and intra-specific means of recognition. Nocturnal species, like most gekkonids and xantusiids, possibly have a very limited ability to see color but, instead, they have a highly developed capability of seeing in poor light conditions.

    Lizards of many different groups possess the capacity to shed their tails when attacked and held by such organs. The vertebrae have a fracture point, usually located in their middle, which breaks under pressure. Once separated from the body the tail will reflexively thrash about and distract the predator from the rest of the animal, which will then flee to safety.

    The majority of lizards lay their eggs un secluded areas or bury them in soft and humid earth. Lizard eggs can be soft- or hard-shelled (mineralized). A number of species, on the other hand, are ovoviviparous, giving birth to miniature replicas of themselves.

Most lizards lay rubbery eggs which need to remain humid in order to survive.

These were laid in an excavation under a rock, by a Puerto Rican giant ameiva, Ameiva exsul.

Susua State Forest, south-western Puerto Rico.

Some lizard eggs are hard-shelled and brittle, like those of birds.

These are the eggs of a common house gecko, Hemidactylus mabouia, laid under a rock.

Cartagena Lagoon National Wildlife Refuge, south-western Puerto Rico.

    Altogether, nine families of lizards are found in the West Indies: Anguidae, Gekkonidae, Gymnophthalmidae, Iguanidae, Polychrotidae, Scincidae, Teiidae, Tropiduridae, and Xantusiidae. Three of these families, the anguids, gekkonids, and scincids, are Cosmopolitan. The others are exclusively American except for a handful of iguanids which invaded and further speciated in some Indo-Pacific islands.

    Among the New World groups, some have very similar morphological, ecological, and behavioral counterparts in the Old World, with which they perhaps have an ancestor in common. Thus the iguanids and polychrotids are paralleled by the agamids of Africa, Asia, and Australia. Similarly, the teiids have a a parallel in the lacertids of the Eastern Hemisphere.

    All the Antillean families of lizards are discussed here save for the polychrotids, which are treated in the next section.

Family Anguidae: Galliswasps and Their Kin

    Anguids are widespread in both the eastern and western hemispheres of Earth. Many taxa have well-developed legs and, as such, are typical lizards. However, in a manner similar to their relatives the skinks, a number of species have greatly reduced limbs, or have lost them altogether, the animals being snake-like.

    Only the subfamily Diploglossinae is native to the region, but the two genera Celestus and Diploglossus are quite species-rich in the Antilles. Celestus has several species in both Hispaniola and Jamaica, and Diploglossus has a few species in Cuba, as well as a single species in Puerto Rico and another in the Lesser Antillean island of Montserrat (D. montiserrati, now possibly extinct). As is the case with West Indian skinks, the region's anguids are ovoviviparous. The young are born fully formed inside the eggs, from which they emerge shortly after the mother lays them. However, sometimes their colors are quite different from those of adults.

    Some West Indian anguids are very elongated lizards and tend to have proportionally tiny legs. When in a hurry to avoid capture, these species press their legs against their shiny bodies and move in a serpentine fashion. Their long and heavy tails are very fragile and are autotomized with ease, if held.

Afraid of the camera, a female Puerto Rican galliwasp, Diploglossus plei, folds its tiny legs against its flanks and hurriedly moves like a snake.

Florida, central Puerto Rico.

Hispaniolan smooth galliwasp, Celestus costatus, subspecies neiba.

Enriquillo National Park, south-western Dominican Republic, Hispaniola.

Hispaniolan keeled galliwasp, (eastern race, Celestus stenurus rugosus), male.

National Botanical Garden, Santo Domingo, southern Dominican Republic, Hispaniola.

Hispaniolan striped galliwasps, Celestus darlingtoni. Valle Nuevo, central Dominican Republic, Hispaniola.

(Photographs courtesy of Mr. Miguel Angel Landestoy).

Hispaniolan khaki galliswasp, Celestus curtissi. Near Gonaives, North-western Haiti, Hispaniola.

(Photograph courtesy of Mr. Eladio M. Fernandez).

Some West Indian anguids are very elongated and, with their tiny legs are taken for small snakes, at first glance.

This is an earless galliwasp, Celestus haetianus surdus. Bahoruco National Park, south-western Dominican Republic, Hispaniola.

Due to certain morphological characteristics - like having no external ears - this species was formerly placed in its own, monotypic genus: Wetmorena.

This is a specialized anguid that inhabits highland broadleaf and pine forests above 1500 meters of altitude.

Jamaican galliwasp, Celestus crusculus. Windsor, north-central Jamaica.

Limestone forest galiiwasp, Celestus barbouri, male. Windsor, north-central Jamaica.

Puerto Rican galliwasps, Diploglossus plei. First two photographs: male. Third photograph: juvenile. Florida, central Puerto Rico.

This is another highly elongated species. It inhabits mesic lowland forests.

This is one of those Antillean reptiles that seems to be extremely rare when it really is not.

Although very common in some areas, its microhabitat of deep leaf litter, often lying on a rocky substrate

into which it flees if alarmed, makes it very difficult to observe even if it is searched for on purpose.

It is seldom ever seen abroad, and then only offers a fleeting glimpse when it crosses a trail.

Family Gekkonidae: Geckoes

    Second only to anoles in the number of West Indian species, this is a Cosmopolitan family. There are geckoes in every corner of planet Earth except the Arctic regions

    Gekkonids are one of the very few families of mainly nocturnal lizards. Some West Indian geckoes are among the giants of their kind, like the Cuban Tarentola americana, the Hispaniolan Aristelliger lar and, in the Lesser Antillean islands, Thecadactylus rapicauda. At the other end of the size scale, geckoes of this region include the smallest known reptiles on Earth: Sphaerodactylus ariasae of Navasa Island, and S. parthenopion, of the Virgin Islands, both about 16 millimeters in snout-vent length.

    Most geckoes have their eyes covered in an transparent scale, like those covering the eyes of snakes. Because their sensitive eyes are perpetually open, the pupil, like a cat's, contracts to a slit in nocturnal species, or to a tiny dot in diurnal ones. If the scales that cover the eyes become dirty, the lizards will lick them clean with their wide, mobile tongues.

Close-up of a female thick-tailed gecko, Thecadactylus rapicauda. Eggleston, south-central Dominica, Lesser Antilles.

A female thick-tailed gecko, Thecadactylus rapicauda, cleans its eye with its tongue.

Eggleston, south-central Dominica, Lesser Antilles.

(Photograph courtesy of Mr. Mel Jose Rivera).

    The majority of gekkonids possess lamellae under their toes. These series of modified scales help them in climbing rocks and trees. Some are able to climb sheer glass, and even hang upside-down from it.

    Geckoes are notorious for being among the most vocal of reptiles. Several large species bark or croak spontaneously to declare their territory. In the West Indies, some members of Aristelliger are good examples of species with this faculty. Smaller species, like Hemidactylus and Phyllodactylus, emit thin squeals and growls when captured or when fighting. Members of Sphaerodactylus seem to be voiceless. (The very name "gecko" is an onomatopoeia of the call of one Asiatic species, the huge and beautiful tokay, Gecko gecko, from which the family obtains its name).

Hispaniolan giant gecko, Aristelliger lar, male. Bahoruco Mountains, south-western Dominican Republic, Hispaniola.

Its Latin epithet ("lar") refers to a household guardian deity or spirit.

(Photograph courtesy of Mr. Eladio M. Fernandez).

Hispaniolan desert gecko, Aristelliger expectatus, male and female.

Neiba, south-western Dominican Republic, Hispaniola.

Jamaican croaking geckoes, Aristelliger praesignis.

First photograph: male, Windsor, north-central Jamaica. Second photograph: male, Negril, western Jamaica.

Third photograph: female, Sheffield, western Jamaica. Fourth photograph: juvenile, Negril, western Jamaica.

Fifth photograph: juvenile, Windsor, north-central Jamaica.

The loud calls of males and females are characteristic sounds in lowland areas of Jamaica.

Caicos gecko, Aristelliger hechti, male. Big Ambergris Cay, Turks and Caicos.

(Photographs courtesy of Mr. Joseph Burgess).

    With their large, unblinking eyes, and often possessing bizarre shapes and colors, many geckoes have a strange, otherworldly appearance and are therefore feared by many people. However, even the largest species are totally harmless to humans, unless provoked into biting.

Some geckoes have a degree of binocular vision. These are male and female Sphaerodactylus roosevelti.

Guanica State Forest, south-western Puerto Rico.

A female Sphaerodactylus klauberi stares at the camera. Guilarte State Forest, central Puerto Rico.

    Geckoes exhibit social interaction patterns that can be highly complex. Tongue-flicks, arched backs, jumps, waving and thrashing tails, head-bobbing, chirps, hisses, and croaks are all part of the communication repertoire that allow geckoes to avoid, threaten, search for, and engage others of their kind. Some of the tiny Sphaerodactylus geckoes can even stand straight up on their two hind legs in order to survey their territories for rivals or mates, highly visual organisms that they are. Unfortunately, since many species are highly secretive or nocturnal, these "shows" are seldom seen by the casual human observer.

    Antillean geckoes belong to two subfamilies. One of them is the Cosmopolitan Gekkoninae, represented in these islands by the genera Aristelliger, Hemidactylus, Phyllodactylus, Tarentola, and Thecadactylus.

    The thick-tailed gecko, Thecadactylus rapicauda, is common in the forests and sub-urban areas of the Lesser Antilles and some of the Virgin Islands. It is most often seen at night, clinging to buildings' walls and tree trunks, lying in wait for passing insects and smaller lizards. Its skin, strikingly leathery to the touch, tears easily and its strange, webbed feet seem to be out of proportion to its body. Usually placid, the occasional individual may still display an egregiously bad temper if held against it will. Across its wide range, the species displays a wide array of color patters depending on population. During the day, an individual may be discovered resting under some object or inside a crevice, in a coiled position that seems to mimic a dangerous - if small and fat - viper.

    The thick-tail is one of the largest geckoes in the Antilles and the Americas. In the West Indies, only Aristelliger lar of Hispaniola surpasses it in size.

Thick-tailed geckoes, Thecadactylus rapicauda, male seeking shelter in a hole in a cave, and female.

First photograph: Cabrits National Park, north-western Dominica, Lesser Antilles.

Second photograph: Eggleston, south-central Dominica, Lesser Antilles.

This species is also found in Central America and northern South America,

aside of the Lesser Antilles and the Puerto Rican bank (in some of the Virgin Islands).

    There are three native members of the genus Hemidactylus in the Antilles: H. palaichthus in Saint Lucia, the widespread H. mabouia, and the Greater Antillean endemic H. haitianus. Collectively called "house geckoes", they are the species most often seen at night inside or about human dwellings.

    The genus Hemidactylus is probably of Old World origins, and American species most probably crossed the Atlantic Ocean from far-away Africa. A few, like the aforementioned H. haitianus, speciated further (in its case, from the African H. brooki), but others, like H. mabouia, are still conspecific with their ancestral population.

    A number of Antillean gekkonids, like Hemidactylus and Thecadactylus, are very adaptable and live in rather diverse habitats, both xeric and humid. Others are restricted to a particular niche, like Phyllodactylus wirshingi, a saxicole found in rocky areas within xeric regions of Puerto Rico. P. hispaniolae and P. sommeri, from Hispaniola, occupy similar habitats.

    And then there are the Lilliputians of the reptilian realm...

    The other gekkonid subfamily present in the West Indies is exclusively American: Sphaerodactylinae. Although only two genera are found these islands (Gonatodes and Sphaerodactylus) there is a great number of species, most of them endemic to single insular banks, and often to small regions within an island. These small lizards depart from what is the norm in their kind, in that many species are diurnal or crepuscular, even if still highly secretive and seldom seen by the merely casual observer. Another of their peculiarities is their general appearance. Instead of the wide and flattened bodies and heads, and the huge eyes of most nocturnal geckoes, sphaerodactylines are rather elongated, their heads are slim and pointed, and have relatively small eyes.

    Gonatodes geckoes greatly resemble their Sphaerodactylus relatives. However, they can be immediately told apart from them by their total lack of adhesive pads on their toes, these simply ending in regular claws. In the West Indian region, they are only found in a few islands. One peculiar habit of these diurnal species is the way they often perch on lower tree trunks, facing down, and in that way resemble tiny anoles. Gonatodes might be the most primitive of sphaerodactylines, the ancestral stock from which other genera evolved. As it happens in Sphaerodactylus, males have a schuteon of flattened scales in front of the cloacal area.

Grenadines clawed gecko, Gonatodes daudini, male and female. Union Island, Saint Vincent and the Grenadines, Lesser Antilles.

(Photograph courtesy of Dr. Jon Boone).

    Sphaerodactylus (dwarf geckoes or "sphaeros") are tiny lizards that inhabit every terrestrial ecosystem in the Caribbean. Unlike other geckoes with series of adhesive lamellae on their toes, members of Sphaerodactylus possess a single, enlarged adhesive scale under the tip of each digit (notice such scales in several of the close-up photographs shown below). These scales are circular, a fact that gives the genus its name, "sphaeros-dactylos": "round finger". The tiny adhesive pad points to the mainly terrestrial habits of most species. Indeed, sphaeros are not as agile at climbing as are many other geckoes and the majority of species in the genus is decidedly terrestrial.

    Among West Indian reptiles, they are second only to anoles in number of species and absolute abundance, with close to 90 species known to date. Unlike most anoles, however, they are mainly terrestrial, although some species will climb trees and cacti, and one, namely Cuba's Sphaerodactylus bromeliarum is, as it name implies, an inhabitant of bromeliads growing on trees. Other species can be found under the peeling bark of standing trees. Those that live on the ground are frequently found under fallen logs and rocks, or while they stalk tiny invertebrates amidst the leaf litter of forests' floors. As with anoles, a number of species have arisen in small cays found near one or another of the larger islands, where the parent species from which they evolved still lives.

    Some groups of species seem to be aligned along ecomorphic lines (see the section on anoles for a description of the concept of "ecomorph"). Among Sphaerodactylus there seems to be, for example, a "xerophile dwarf" ecomorph. These tiny species are drab in color, have short, rounded snouts, and inhabit rather humid microhabitats in xeric forests and deserts in the Greater Antilles. Forms that may be included in this type are S. homoglaux and S. ariasae of the Hispaniolan insular bank, and S. townsendi, S. nicholsi, and S. parthenopion of the Puerto Rican bank. "Forest giants" are much larger species, some with bright patterns, and include S. roosevelti and S. klauberi of Puerto Rico, S. mariguanae, of the Bahamas, and Sphaerodactylus vincenti of the Lesser Antilles. Generalists include S. argus of Cuba, Jamaica, and Mesoamerica, S. difficilis of Hispaniola, and S. macrolepis of Puerto Rico.

    The fact is that aside from these generalizations, the lines dividing sphaerodactyline ecomorphs are presently very poorly defined, as compared to those dividing ecomorphs among anoles.

    Some species can be extremely abundant in some habitats, like the leaf-litter ground cover of littoral sea grape (Coccoloba uvifera) forests and of lowland xeric forests. Every acre of such places may harbor from hundreds to tens of thousands of individuals. However, in spite of being present in almost every terrestrial habitat in the Antilles and of being mostly diurnal, sphaeros are so small and secretive that one can spend months without seeing one unless one looks for them.

Many sphaeros are abundant, yet difficult to see in their habitat.

This is a female Guantanamo Bay sphaeros, Sphaerodactylus ruibali. Guantanamo Naval Base, Guantanamo, south-eastern Cuba.

(Photograph courtesy of Mr. Joseph Burgess).

    Partly because sphaeros are so tiny, the different species are often difficult to tell apart. Some are divided into several subspecies, which themselves can be either very similar or strikingly different. Sphaerodactylus macrolepis is one of such taxa. It ranges widely in the Puerto Rican island bank, where it is found everywhere except in some xeric areas. Its biogeography is peculiar in that it is one of the few native Puerto Rican reptiles that is endemic to more than one insular bank, since it is also found in Saint Croix, United States Virgin Islands (possibly as an unwitting man-made introduction).

Sphaeros are the smallest terrestrial vertebrates on Earth.

This is an adult male Sphaerodactylus nicholsi, photographed with a United States ten-cent coin for scale.

Guanica State Forest, south-western Puerto Rico.

    With their elongated bodies and narrow, pointy heads and snouts, sphaeros are very picturesque. Some species are colored in drab, monochromatic grays or browns, while others exhibit gorgeous and complex patterns of bands, spots, or stripes. These can be on beige, yellow, orange, slate blue, or purplish background colors. In many species, one or both sexes have a dark patch above the shoulders or on the back. This patch often encloses two light ocelli, and the pattern might fulfill a color-disruptive function or might deviate the attention of a predator away from the lizard's head.

Many sphaeros have a patch of dark scales surrounding two white ocelli. This pattern may have a dissuading purpose, serving as false eyes to intimidate some predators.

This is a female Puerto Rican eyespot sphaero, (northern race, Sphaerodactylus macrolepis guarionex). Caguas, east-central Puerto Rico.

    Some species of Sphaerodactylus exhibit a very strong sexual dichromatism. Sometimes the dissimilarity is enough for the sexes to look like different species (see the photographs of Spharodactylus macrolepis spanius and Sphaerodactylus torrei, lower down on this page). In other species, sexes are alike and can only be distinguished by the presence, in the males of most species, of a patch of flattened scales before the vent. In some species, these extend into the ventral surface of the thighs.

Cuban broad-banded sphaeros, (Guantanamo Bay race, Sphaerodactylus torrei spielmani),  male and female, captive specimens.

(Photographs courtesy of Mr. Joseph Burgess).

A male Sphaerodactylus macrolepis ateles, has a pre-anal patch of flattened and

un-pigmented scales, extending somewhat unto the ventral surface of its thighs.

This is a trait in the males of all species of the genus.

Mayaguez, western Puerto Rico.

    For all their tiny size, sphaeros seem to be pugnacious creatures. That, together with the fact that many other animals prey on them, makes it rare to find an individual without a regenerated tail and pieces of skin. In some species, complete tails can be told by their black and white tip.

    Female sphaeros lay single eggs with a calcareous shell, only a few millimeters in length.

    Some sphaeros are ecological generalists, and are highly adaptable to diverse situations. The next eight species of Sphaerodactylus are more or less widely distributed in their islands of origin. They are found almost anywhere their needs for a specific habitat are met.

    Other sphaeros are much more restricted in their distribution, or live only in a particular habitat, or even microhabitat. This is the case especially with some very small as well as "giant" species. The Hispaniolan Sphaerodactylus omoglaux lives only in the desert of the Valle de Neiba-Cul de Sac plain. The Puerto Rican S. roosevelti exists only in the xeric forests and cactus scrub of southwestern Puerto Rico. Similarly, S. beattyi is a xerophile that is found only in a small portion of an already small island: the xeric forests and savannas of eastern Saint Croix, United States Virgin Islands.

    The next three species are examples of habitat specialists.

    Lesser Antillean sphaeros occupy similar habitats to those of the Greater Antilles. Most are related among themselves.

Leeward banded sphaero, Spherodactylus sputator. Vitet, Saint Bartholomew, Lesser Antilles.

(Photograph courtesy of Mr. Karl Questel).

Southern leeward sphaero (Dominican race, Sphaerodactylus fantasticus fuga) female.

Cabrits National Park, north-western Dominica, Lesser Antilles.

Saint Lucian sphaeros, male and female. South-eastern race, Sphaerodactylus microlepis thomasi.
Maria Major Island, off south-eastern Saint Lucia, Lesser Antilles.

Family Gymnophthalmidae: Worm Lizards

    Sometimes considered a subfamily of the family Teiidae (above) this group contains several small West Indian species. Gymnophthalmus pleii and G. underwoodi inhabit some of the Lesser Antillean islands (the second species is also found in the South American mainland). Aside from their much smaller size, they are superficially very similar to the skinks of the genus Mabuya that are found in the same islands. However, they are immediately distinguished from them by their tiny size, and for having only four toes on the anterior feet.

    A single lizard of the genus Bachia (B. heteropus) which also belongs to this family, is found in some of the Lesser Antilles and is shared with South America.

Family Iguanidae: Iguanas and Their Kin

    Iguanids are mainly a New World family of lizards. Only a few, relict members of the group live outside the Americas, inhabiting the Galápagos Islands, Fiji, and Madagascar, all these being islands in the Indo-Pacific Ocean. Many iguanids are terrestrial although, especially in the Neotropics, many have adapted to a life on trees. In size, they range from tiny creatures measuring four centimeters in total length to the heavyweights among American lizards, namely the enormous and powerful cyclurid iguanas of the Greater Antilles and the Bahamas.

    Iguanids are represented in the West Indies by two groups: the sister genera Cyclura and Iguana, and also by Ctenosaura.

    All these large iguanids are mainly herbivores, though they are facultative carnivores. Both Iguana and Cyclura may devour small mammals and birds when these are within their reach. However, this behavior is never habitual.

    Save for the ground sloths and some huge capromyd rodents - both groups are now extinct - the iguanas of the West Indies are the largest native terrestrial herbivores in these islands. They are important seed dispersers in the ecosystems where they belong, by eating certain fruits and then excreting the still viable seeds.

Southern Bahamas rock iguanas, (nominate race, Cyclura carinata carinata), females feeding on turk's cap cacti fruits.

Their tough, scaly skins protect them from the plant's fierce thorns.

Big Ambergris Cay, Turks and Caicos.

(Photograph courtesy of My. Joseph Burgess).

    Some of these large reptiles are good colonizers of new areas. The two Iguana species of the Lesser Antilles have been seen rafting on masses of vegetation, especially after storms, or swimming in the open sea among the islands, even in good weather. Whatever would entice a lizard to make such a journey through its own volition is not easily understood. It may be a consequence of occasional overpopulation and the subsequent depletion of resources. Whatever the case may be, it is evidence of the dispersal abilities of these fascinating organisms.

    At least as far as external morphology is concerned, the difference between the genera Cyclura and Iguana is not fully clear-cut. The very name of the first genus (from the Greek "cyclos" - "circle", and "urus" - "tail") makes reference to the whorls of enlarged spine-like scales surrounding their tails. This trait is absent in Iguana but, in fact, one member among the cyclurids, namely Cyclura pinguis of the Puerto Rican insular bank, lacks those, as well. Perhaps the species of the two groups are all Iguana, but the matter does not seem to be settled.

    Members of the genus Cyclura, the rock iguanas, are endemic to the Greater Antilles and the Bahamas. The genus formerly inhabited some of the northern Lesser Antilles, as well. Some of them, like the Cuban, Grand Cayman's, rhinoceros, Anegadan, and Mona Island's rock iguanas, are the largest lizards of the Americas. In fact, among West Indian terrestrial reptiles, they are surpassed in size only by the two native crocodiles and some of the Boa and Epicrates snakes.

    Cyclurids mainly inhabit arid lowland forests, and are among their most picturesque denizens. Ponderous beasts when they contentedly patrol their territories with an almost crocodilian gait, they can run as fast as a man when fleeing danger. Usually timid and flighty, their temper may change suddenly when they feel cornered. A large individual can turn into a reptilian chainsaw in the blink of an eye and its sharp teeth, claws, and serrated tail might leave an assortment of welts and gashes on the human who carelessly attempts to hold it against its will.

    Cyclura iguanas are mainly terrestrial, though the occasional individual will climb a tree. At night or when threatened they seek refuge in burrows excavated with their powerful legs. For such formidable creatures, some species can be very skittish, but they quickly become accustomed to human presence in places where they are not harassed or hunted. In a few places they concentrate in great numbers due to people who feed them table scraps.

    Sadly, almost all populations of this genus are threatened as a result of any combination of habitat destruction, introduced predators, and hunting by humans. In fact, one species is already extinct: the Navassa Island's rock iguana, Cyclura onchiopsis.

    The genus Iguana has one species endemic to the Lesser Antilles, I. delicatissima. Another, the common iguana, I. iguana, is naturally present in the Lesser Antilles, north to and including the Puerto Rican bank (in the Virgin Islands) but also ranges far into South and Central America, north to Mexico.

    Both members of Iguana can attain more than two meters in length. However they are not as massive as the largest species of cyclurids. By comparison, they are slender and long-tailed, as well as far more partial to climbing trees. Common and Lesser Antillean iguanas are habitually docile animals. However, as happens with their Cyclura relatives, antagonizing a large adult frequently renders unpleasant consequences. A frightened individual on a tree will think nothing of throwing itself from amazing heights, from its perch to the ground or water, and thus escape its attacker.

    Where they live in sympatry, the way to distinguish this two very similar lizards is by observing the spot right behind and under the angle of the jaws. There, Iguana iguana will have a single, very large and round scale. Iguana delicatissima lacks this trait, and that patch of skin is simply covered in small scales.

    Both species begin their lives being a bright emerald green color, the common iguana with more or less clearly pronounced brown bands. However, as the animals mature, the green color is gradually replaced by darker hues of gray, red, brown, or blue. Very large and old males may simply be a greenish gray or brown, especially in their heads and anterior half of the bodies. Adult Lesser Antillean iguanas are especially prone not to be green, while several populations of the common iguana are melanistic. The Saint Lucian population of Iguana iguana has two horns on its snout and seems to be genetically distinct enough to represent an endemic taxon.

    The common iguana is very abundant in some islands, like Saint Thomas, in the United States Virgin Islands. There, it can be found by the dozen even in residential areas, as it seems to have adapted marvelously to human presence. It has also been introduced by humans outside its native range, to places like Puerto Rico (where it would most probably have arrived on its own, eventually) and southern Florida, where it is now a veritable pest as it feeds voraciously on garden plants. Ironically, while in such places it flourishes to the point of being out of control, it is endangered in some of its natural range in Central America, where many people consider it a delicacy. (Indeed, their flesh is quite tasty).

    The Lesser Antillean iguana is not as common as its sister, although it lives in reasonable numbers in some islands. This huge, magnificent lizard has suffered its share of hunting by humans and habitat degradation. This last is caused by direct deforestation caused by man, and by the negative impact caused by feral cattle, especially goats, on the native vegetation. Also, mongooses, cats, and dogs prey on hatchlings and juveniles.

    In places where its habitat has been severely altered, Iguana delicatissima suffers a peculiar sort of extinction risk consisting in the dissolution of its gene pool. This happens when it hybridizes with the common iguana, the offspring belonging to none of the parent species.

    The genus Ctenosaura, the spiny-tailed iguanas, is found in some extreme western Caribbean islands, being there invaders from Central America. Although not as large as some Cyclura, they are similar, and are likewise mainly herbivorous, as well as have tails with spiny scales.

Black spiny-tailed iguana, Ctenosaura similis, male. Utila Island, off eastern Honduras.

The species also inhabits some eastern Caribbean islands.

(Photograph courtesy of Mr. Joseph Burgess).

Family Scincidae: Skinks

    Although they comprise one of the most species-rich families of lizards in the World, skinks are very poorly represented in the Caribbean islands. The only genus present is the almost Cosmopolitan Mabuya, which has colonized many oceanic islands, and has a few species in the region. The Lesser Antillean skink Mabuya mabouya is widespread throughout those islands. The Greater Antillean skink, M. sloanei, is found in the Bahamas and the Greater Antilles save for Cuba. Another two West Indian species are single-island endemics: M. macleani, which is only found in tiny Carrot Rock (British Virgin Islands), and M. lineolata, which is Hispaniolan.

    Antillean species are mostly terrestrial, and establish territories on and among piles of rocks and near downed tree trunks. However, they can easily climb trees. Although of a more phlegmatic disposition than the ameivas which they superficially resemble, and easier to approach, they are seldom seen away from cover, and will dart toward their hiding place if molested. Antillean Mabuya are ovoviviparous, "giving birth" to a few young at a time. These are born enveloped in egg membranes which they rupture moments after oviposition.

Family Teiidae: Ameivas, Whiptails, and Their Kin

    Teiids are small to large lizards of the Americas, collectively called "whiptails" because of the long tails of many species. They are the New World counterparts of the lacertids of Eurasia and Africa, and their range extends from temperate North America to temperate South America. While most members are small to medium-sized, the South American tegus of the genus Tupinambis can be quite large. Indeed, they are the ecological equivalents there of some of the Varanus monitors of Old World.

    Many Caribbean islands are inhabited by teiids. Those of the genus Ameiva are the most frequently seen, and many of the roughly 34 described species are restricted to the Antilles.

    Ameivas (and many other teiids) are omnivores that will eat anything that is edible and small enough to swallow, animal or plant. Nervous and jittery, some ameivas are among the fastest lizards in the World. An attempt to chase and capture in the open an individual of the larger species is usually an exercise in futility. Some species of Hispaniola and Puerto Rico are able to run on their hind legs for short distances.

Ameivas are opportunistic omnivores that will eat almost anything edible.

These male and female Neotropical ameivas, (Lesser Antillean race, Ameiva ameiva tobagana), gorge themselves on discarded food at a campsite.

Grand Anse, south-western Grenada, Lesser Antilles.

Neotropical ameiva, (Lesser Antillean race, Ameiva ameiva tobagana), male. Grand Anse, south-western Grenada, Lesser Antilles.

This photograph shows the horizontally elongated pupil of many teiids, which grants them excellent vision cued on movement.

    Most Caribbean ameivas are xerophilic denizens of beaches, savannas, dry forests, and deserts. However, a few Lesser Antillean forms inhabit even rain forests as long as there are open sites for them to sunbathe.

    Forms that live in sympatry have speciated and segregated ecomorphically according to differences in size, morphology, and the niche they occupy. Thus, they end up differing from sister species within the same island bank, and resembling unrelated species in other island banks. Such is the case especially in Hispaniola and Puerto Rico, each with a large species unrelated to the other (A. chrysolaema and A. exsul, respectively) that is basically brown or gray in color and occupy shadier, more humid areas. Another two species (A. lineolata in Hispaniola and A. wetmorei in Puerto Rico) are dwarves with striped color patterns and metallic blue tails, and live only in the driest, most sunlit areas. Again, and in true ecomorph fashion, these two are unrelated, but are sisters to the previously mentioned, larger species in their same islands.

    The stripes and vividly-hued tails of some ameivas partial to dry regions is a color pattern common in many xerophilic lizard species all over the World. In regions far away from the Caribbean, desert-dwelling teiids, scincids, and lacertids rely on this same sort of disruptive color pattern to avoid easy detection by predators and to attract their enemies' attention to their tails, instead of the more important head and body. (Even some mammals, like zebras, possess shape-disrupting, striped patterns).

Ameiva wetmorei, female. Guanica State Forest, south-western Puerto Rico.

The striking colors of this and similar species (like A. taeniura and A. lineolata) are actually a disruptive pattern.

When one searches for them, it is quite difficult to distinguish them from the sunlight-mottled

leaf litter and rocky ground on which they are usually found. A bird of prey and other such predators

will tend to focus on and attack the bright tail, often allowing the lizard to escape to safety.