Last updated 27 March 2012: added link to Heloderma.

A Rough Guide to

THE LIZARD FAMILIES

What follows is a rough guide to the various families of the lizards around the world. This is technically known as the taxonomic classification of lizards. Apart from the interest value, it may help you when trying to ascertain care requirements for a particular species.

Lizards, snakes and amphisbaenians together form the Order Squamates. Lizards form the sub-order Sauria, while snakes and amphisbaenians form the sub-orders Serpentes and Amphisbaenia respectively.

The families of the lizards are grouped into four infra-orders, super-families, or ancestral lines: Gekkotans, Iguanians, Scincomorphs and Anguinomorphs. Some experts add a fifth, Varanoidae (formerly known as Platynota according to Bellairs (1968)), which I will also adhere to.

Finally it should be noted that lizard taxonomy is in a state of constant revision at the moment, with families, orders, etc being shunted around every few years. Although the classification that follows is broadly correct (I have borrowed largely from Chris Mattison's Lizards of the World, 1989), you should be aware that it may change or that there are alternative models. Lest this sound too vague and woolly to be worth reading, I should add that the family descriptions at least are fairly accurate.

The term Old World is used here according to standard usage to include Europe, Africa, Asia and Australia. The term New World denotes the Americas.

The italicised name in brackets is the proper Latin scientific name.

Those families marked * are extremely rare. They are hardly ever seen in captivity and little is known of their natural history.

Iguana line (Iguanians)

Agamids (Agamidae: 300 species)

Agamids are only found in the Old World. They are very similar to the iguanids of the New World in many ways (sometimes extraordinarily so), but differ in the arrangement of their teeth. Agamids include some well-known and popular pets such as Water Dragons, Bearded Dragons and Uromastyx, and also Frilled Dragons and Sailfin Dragons. As a rule agamids tend to be medium-sized lizards, insectivorous or omnivorous and reasonably tameable. Most seem to inhabit forest or jungle, but the Uromastyx come from arid or hot desert areas. Apart from the well-known species described above, other agamids are not well-known within the pet trade and their care requirements are difficult to track down.

See also A Look at the Agamids

Iguanids (Iguanidae: 650 species)

Iguanids are the New World counterparts of the Agamids. Although people tend to associate the word iguanid with the well-known Common or Giant Green Iguana Iguana iguana, this is only one species in a very varied family that includes desert-dwelling species as well as those from humid jungles. Recently the family has been broken up into smaller units by some scientists, but traditionally it has included such well-known lizards as the Green Iguana, Chuckwalla, Desert Iguana, Collared Lizard, Swifts and Horned Lizards. Requirements vary for these lizards, but as a rule the largest members of this family are entirely herbivorous, eg the Chuckwalla and Green Iguana, whereas the smaller members such as swifts tend to be insectivorous.

See also Iguanid Lizard Guide; List of Iguanid Genera; Anole Lizards

Chameleons (Chameleonatidae: 85 species)

The chameleons need little introduction. Suffice it to say that their physical characteristics vary so much from the standard saurian structure that some taxonomists proposed putting them in their own sub-order, ie elevating them from being a family of lizards to being something different to lizards altogether. Chameleons are almost entirely found in Africa and Madagascar, with a very few species occurring as far north as Asia Minor and Spain and Portugal. They are very demanding creatures in captivity, needing very well-planted cages, humidity but with plenty of ventilation, and a variety of insects to feed upon. They are also somewhat anti-social reptiles, more so than possibly any other family.

Anguid line (Anguinomorphs)

Anguids (Anguidae: 75 species)

The anguids are found in North America, Europe and Asia Minor. They have a strong tendency to leglessness, including such species as the North American Glass Lizards (Ophisaurus) and the European Slowworm and Scheltopusik. Of the four-legged species, perhaps the best known is the Gerrhonotus, better known as the Alligator Lizard. Virtually all members of this family have a distinguishing lateral fold running along their bodies, regardless of how many legs they possess. Most of these lizards hail from temperate to moderately warm climates, and some of the legless ones are surprisingly long-lived.

See also A Brief Look at the Anguidae

Xenosaurs (Xenosauridae: 7 species)

The Xenosaurs (also known as "Crocodile Lizards") are a small and cryptic family comprising a total of two genera and four different species, one from China and the others from Mexico. Little is known about them, either their natural history or their captive requirements, although some success has been met recently with the rare Chinese Crocodile Lizard (Shinosaurus). This xenosaur hails from areas of high moisture, often a semi-aquatic habitat such as a stream. The six Mexican species are confined to the eastern areas, in mountainous regions. All seven species give birth to live young. These are fairly demanding lizards for captivity, and more research needs to be done.

Anniellidae (Anniellidae: 2 species)

These small legless lizards are restricted to the location of California and Baja California, Mexico. Like most legless lizards they are easily distinguishable from snakes by their movable eyelids. Nocturnal, they live in sand or leaf-litter, feed mainly on invertebrates and give live birth. This family is often considered part of the Anguidae instead.

See also A Brief Look at the Anniellidae

Skink line (Scincomorphs)

Skinks (Scincidae: over 1000 species)

This is by far the biggest family of lizards, with over 1,000 different species covering virtually every continent of the world. Unlike the geckos, however, they do vary somewhat in form. Nevertheless a "typical skink" could be described as 6-12" long, with smooth shiny scales, often reduced limbs, and a nervous, shy temperament that causes it to spend most of its time buried in leaf litter or sand. From one point of view this is a pity as many of them are beautifully coloured, eg the Fire Skink (Lygosoma fernandi) and Berber Skink (Eumeces schneideri) from Africa or the Ocellated Skink (Chalcides ocellatus) from Europe. In the Australo-Pacific area there are a number of large skinks which are deservedly popular in the pet trade and which tend to be calmer than their smaller relatives. Especially well-known are the Blue-Tongue and Pink-Tongue Skinks (Tiliqua spp), but the Monkey-Tailed or Solomons Skink (Corucia zebrata) is also popular, and the spiky-looking Cunninghams Skink (Egernia cunninghami) can also be purchased nowadays. It is hard to lay down general requirements for skinks as they vary so much in their habitat, but as a rule the smaller skinks are associated with temperate forest or woodland.

See also A Guide to Skinks

Lacertids (Lacertidae: 200 species)

The Lacertid family are traditionally associated with Europe, although some of its members are also found in Africa and Asia Minor. The European species at least have moderate temperature requirements, often hailing from areas with warm summers but severely cold winters (eg the Balkans), and the Common Lizard is sometimes found beyond the Arctic Circle Most lacertids are on the small size, notably the genus Podarcis (Wall Lizards) which normally never reach more than 12". Of the genus Lacerta, however, there are several that reach 12-18", and the popular Eyed Lizard can reach 24-36" in length. There is not much information dedicated to the Lacertid family, but with the increased captive breeding of these lizards this situation will hopefully change soon. They are considered relatively easy to care for, with the exception of some of the lesser-known species (especially Eremias).

See also Gallotia lizards of the Canary Islands; A Guide to Lacertids



Teiids (Teiidae: 227 species)

The Teiids are found in the New World, mainly South America, and are often considered the New World equivalent to the Lacertids, many of the smaller members being similar in appearance and structure. The family can conveniently be considered as two halves, the smaller and larger. The smaller ones such as ameivas are characterised by long bodies and tails and rapid flight, and in captivity need largeish quarters to avoid stress. They are usually insectivorous. The larger ones include the well-known tegus, in some ways New World equivalents to the monitors and blessed with a similar temperament, at least initially. The large Caiman Lizard is also a teiid. Parthenogenesis, the ability of a female to produce offspring without male fertilisation, is a notable feature of many of the smaller species of teiids. Recently the subfamily Gymnopthalminae was raised to full family status, but older literature still treats the two groups as one.

See also A Guide to Teiids | A Brief Look At The Gymnophthalmidae

Girdle-Tailed Lizards (Cordylidae: 50 species)

An entirely southern and eastern African family. Cordylids are almost always spiky-looking creatures, ranging from 4-6" to 24". Most are insectivorous, but some take plant matter as well, usually the larger members of the family. Cordylids are often found around rocks and often live in colonies. High temperatures are usually the norm for these lizards in captivity.

See also A Brief Overview of the Cordylidae

Plated Lizards (Gerrhosauridae: 50 species)

Like the Cordylids, to which family they were formerly reckoned to belong, Gerrhosaurids are a southern and eastern African family and are also found in Madagascar. They are normally 12-30" and covered in flat, armoured scales (hence their popular name). Most are insectivorous, but some take plant matter as well, usually the larger members of the family. Like the Cordylids they are often found around rocks, but are definitely less sociable than the girdle-tailed lizards. Again, these lizards tend to need highish temperatures in captivity.

See also Plated Lizard Guide.

Xantusids (Xantusiidae: 16 species)

A family of small, gecko-like lizards from North and Central America, often referred to as "night lizards". These have been described (a little unfairly) as nondescript, but the few that are seen in the trade are normally fairly easy to care for.

*Dibamids (Dibamidae: 10 species)

Collectively also known as "Blind Lizards", this is another little-known and curious family of virtually limbless lizards who live a burrowing existence. Indeed, so closely are they adapted to the underground life (eyes covered with scales, complete loss of front limbs, minimal hind limbs existing only in the males) that their relationship to other lizards is uncertain: some have even suggested they are closer to the amphisbaenians or the snakes. All are small, less than 8 inches in length, and all are extremely rare. One species, Anelytropsis papillosus, is found in Mexico and used to be considered a family in its own right: the other nine are all from Asia and Australasia. Virtually nothing is known of their mode of reproduction.

Gecko line (Gekkotans)

Geckos (Gekkonidae: 830 species)

Geckos are the most ubiquitous of lizards, being found on every continent and often in human habitations, where they generally perform the useful service of consuming insects and other arthropods not wanted within the home. Geckos are on the small side, the largest extant species (the New Caledonian Rhacodactylus) being 14" long. Virtually all of them lack the normal scales but have instead tubercles on their soft skin, and many lack eyelids, having instead a snake-like transparent brille (spectacle) covering the eye. Some of this large family are established favourites in captivity, notably the Leopard Gecko, closely followed by the Tokay Gecko and the Fat-Tailed Gecko, and of course the beautifully-coloured Day Geckos. Most geckos are relatively easy to care for in captivity, and there is a good deal of information on the better-known species. Day Geckos are a little more demanding due to dietary demands. Geckos are also the most vocal of lizards, often communicating with barks, clicks or even a sort of call or chuckle.

See also Gecko Page.

Pygopods (Pygopodidae: 31 species)

The "snake lizards" are confined to Australia and nearby islands (eg New Britain, New Guinea) and are all limbless, although like many such lizards they retain the vestiges of their hind limbs, here in the form of small scaly flaps at each side of the cloaca. Like snakes, they lack movable eyelids and external ear openings. Strangely enough, though, they apparently communicate by vocalisation, and this and a number of other characteristics seems to make them relatives of the geckos. The largest, Lialis burtoni, grows to about 2ft: many are much smaller, 8" or less. The main disadvantage of the larger Lialis lizards from a keeper's point of view is that they prey primarily on lizards (skinks and geckos). The Pygopus genus, on the other hand, feed mainly on insects. Despite their appearance, snake lizards do not burrow.

See also A Brief Look at the Pygopodidae

Varanid line (Varanoidae)

Helodermatids (Helodermatidae: 2 species)

The helodermatids are just two species that are related to the monitor family. They are the only two venomous lizards in the world, the Gila Monster from Arizona (Helodermid suspectum) and the Mexican Beaded Lizard (Helodermid horridum). Both are rare in captivity and command high prices, and both are dangerous if they bite as there is no known antidote for their venom. Both are also endangered, mainly due to loss of habitat. Despite their fearsome reputation, however, these are for the most part somewhat sluggish reptiles that are normally well-behaved in captivity. The Gila Monster hails from the desert, but despite this likes to spend hours soaking in water. The Beaded Lizard seems to be from less arid areas and is somewhat bigger and less docile. Both prey on small mammals and birds, and the Gila Monster in particular has a fondness for eggs.

See also Heloderma

Varanids (Varanidae: 30 species)

These are the famous (or infamous) monitors, about 60 species found in Africa and especially Asia and Australia. Although they are renowned for being the giants of the lizard world, there are also a number of "dwarf" species, virtually all of which unfortunately come from Australia and are therefore hard to come by. Despite their charisma, most of the larger monitor lizards make difficult captives due to the demands of space and also an aggressive temperament. Most are from hot environments, and practically all are carnivorous scavengers who will eat readily. They likewise all have sharp claws, sharp teeth and a strong tail that is not dropped but instead used as an effective weapon. The Komodo Dragon needs no introduction, being the largest lizard in the world and living in its own national park in Indonesia, where it is restricted to three islands. Its extinct relative, Megalania priscus of Australia, was actually twice as long at 20ft, but disappeared 15,000 years ago. Far more likely to be seen in captivity are the Savannah and Nile Monitors of Africa, the Water Monitor and Crocodile Monitor of Asia, and the Emerald Green Tree Monitor of Australia. In sum, the requirements for this family of lizards are easy to comprehend but normally difficult to meet.

See also Varanids (Monitors) page.

*Lanthanodontids (Lanthanodontidae: 1 species)

The only species in this family, better known as the Earless Monitor (scientific name Lanthanotus borneensis), is an enigmatic and still little-known creature that is related to the helodermatids and monitors but lacks external ear openings. Very few have been found, let alone kept in captivity, but it has been conjectured from this lizard's anatomy and behaviour that in some ways it forms a link with the snakes.

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