Added 8 December 2002. Last updated 9 February 2025: added link to Callopistes and Cnemidophorus and updated Introduction and Bibliography.

A look at the

TEIIDS

Family TEIIDAE

Introduction

The teiids are one of the smaller lizard families, found entirely in the New World and predominantly in South and Central America, with a fair number in the Caribbean and some species reaching the southernmost parts of the USA. The family was reduced in size when the subfamily Gymnopthalminae was raised to full family status, although the difference between the two groups is only detectable by specialists.

Teiids are not a family name to most people, but in fact most people in the area of their distribution will have seen them. Members of the genera Ameiva, Aspidoscelis and Cnemidophorus are particularly widespread throughout the New World. Most herpetophiles will also be acquainted with the largest members of the Teiidae, the notorious tegus (Tupinambis sp.) which in some ways can be considered analogous to the Old World monitors although not closely related. In fact the Teiidae can be considered most closely related to the Lacertidae of the Old World (Europe, Africa and Asia): like them they have well-developed limbs and long tails, while there is a fairly high occurrence of parthenogenesis (all-female reproduction) in the genera Aspidoscelis and Cnemidophorus in particular (as well as Kentropyx and Teius) that corresponds to the same phenomenon found among many Lacerta species, particularly in the Caucasus and Asia Minor. Unlike the Lacertidae, however, the head shields of the Teiidae are not fused to the bones of the skull, and their teeth are not hollowed at the base.

Teiids as a rule are somewhat underrepresented in the animal trade, with a few important exceptions. This is partly because they have a reputation for being slightly more "tricky" in captivity, with the large tegus being stroppy to say the least and the smaller species (especially the Ameiva) being highly-strung and requiring large cages and plenty of hiding spaces. The Caiman Lizard (Dracaena) are not only large but are specialised mollusc feeders with a requirement for a large body of water that puts them beyond the reach of most private collectors. On the plus side, Bartlett and Bartlett note that most teiids are rather generalist in their diet, eating insects and other prey but also fruits and palm nuts. Mattison has a chapter dedicated to the keeping of Teiidae, although he is fairly cool about the captive potential of the larger species.

As noted above, the Teiidae were traditionally divided into two subfamilies: the Teiinae and the Gymnopthalminae. The removal of the latter group leaves the one which however contains the best-known teiid genera. It must be said that in comparison with other lizard families (and indeed other reptile families) there is still little known about many of the species in the two groups, a situation that will hopefully be rectified in the near future.

In 2002 it was proposed that the genus Cnemidophorus be split into two with the creation of a new genus, Aspidoscelis: this change now seems to be universally accepted and as at 2011 we have included it here.

As at 2023, further revisions to the family have been made over the past decade or so, with new genera being created and many species reassigned. The tegus are now in fact two genera, the new one being Salvator. Similarly the whiptails have been further refined in classification, having formerly been assigned to just the two genera.

The following is a guide to the teiid genera.

NAVIGATION: As this is a large page we have placed a couple of navigation links in each genus box. Click on "B" to go to the Bibliography, or "I" to go back up to the index (Quick Links).

Bibliography - Teiidae

There seems to be no one single work (at least outside academic circles) dealing with the family Teiidae and/or the Gymnopthalmidae in their entirety. Of all the teiids and gymnopthalmids, tegus, ameivas and whiptails are usually the only ones mentioned at all in general books on lizard keeping, with the Dracaena species occasionally warranting a mention (in eg Sprackland). There is plenty of scientific literature available on Cnemidophorus, as these have been widely studied in the US, but arguably this may not be terribly accessible or even useful to the aspiring keeper.

Animal Life Encyclopedia Volume 6: Reptiles, Grzimek,1975 provided an overview of the general characteristics of teiids and of some of the lesser-known families.

Index of teiid-related articles from herpetological magazines.

Bibliography: specific genera

Giant Lizards, Robert Sprackland, TFH 1992. Contains brief but useful overviews of the tegus (Tupinambis), caiman lizards (Dracaena) and Callopistes flavipunctatus, the Monitor Tegu. This is a nice but expensive book, so if you are looking just for care details on the above-mentioned species, you may need to try one of the books below.

The General Care and Maintenance of Popular Monitors and Tegus, Michael Balsai, Advanced Herpetocultural Library. This is an updated version of Balsai's previous book in the same series, The General Care and Maintenance of Savannah Monitors. Apart from an enlargement of the care notes, mainly to include observations from other sources (mainly keepers!), the book includes an increased number of species, including a few of the desirable Australian monitors and the popular tegu. I do however have reservations about the author's apparent propensity for a rodent-based diet for large lizards - check diet with other sources, including keepers. The taxonomy on tegus is perhaps somewhat out of date as well.

Monitors, Tegus and Related Lizards, R D & P Bartlett, Barrons. The Bartletts are always informative and have had a good deal of experience with most cold-blooded terrestrial vertebrates. We particularly recommend this book if you wish to purchase one of the less commonly available monitors or a tegu. In addition there are useful sections on Callopistes (the Dwarf and Monitor Tegus) and Dracaena, the Caiman Lizards.

A-Z of Lizard Care, Bartlett & Bartlett, Barrons, 1995. Contains not only sections on tegus and monitors but also a brief but useful section on Ameiva species.

Echsen [Lizards] Vol 2, Rogner, Ullmer Verlag, 1992. Usually a very good source of information, although it has been pointed out to me by one source in at least one section there was a "theoretical" guess as to the captive requirements of a particular species that is in reality very hard to keep alive. However, of all the books I have found so far, this is the only one that offers any details on the lesser-known members of the Teiidae and Gymnopthalmidae. The notes on Callopistes are particularly interesting as Rogner discusses the details of winter dormancy. This book (and Vol 1) are available in English translation, but are substantially more expensive than most of the volumes mentioned above with the exception of Sprackland.

Links

So far we have not been able to find any links to sites dedicated to or dealing with the Teiidae as such. If anyone knows of any we would be glad to hear from them.

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