Class: Reptilia
Order: Squamata
Family: Teiidae
Genus: Tupinambis
  • Colombian Black and White, T. teguixin
  • Blue, T. teguixin sp.
  • Gold, T. nigropunctatus
  • Argentine Black and White, T. merianae
  • Red, T. rufescens
Tegu is the common name for a species complex of large lizards. The name comes from the Nahuatl (Aztec) tecoixin or teguexin**, meaning lizard. Tegus are large, carnivorous lizards indiginous to South America. They are the ecological equivalents of the varanid family, and are an often-cited example of convergent evolution.

The Black and White, Gold and Blue tegus are all smaller members of the genus, growing to a size of roughly 3 feet and weighing 7 pounds. They have similar diets and behaviour, and inhabit similar climates. These three species can be found as far north as Colombia and as far south as Argentina. They are almost exclusively carnivorous, and feed upon insects and other invertebrates when young, moving to frogs, lizards, snakes and all kinds of eggs as they reach adulthood.

The Red tegu, on the other hand, is larger than its congenerics (up to 4.5 feet and 25 pounds), and has a differnt diet. Its native range is restricted to northern Argentina. They prey upon small mammals, lizards and snakes in the wild, but their principle sustenance comes from insects and fruit.

Unlike monitor lizards, the tegus are capable of caudal autonomy (dropping their tail) and subsequent regeneration. They are hunted by South Americans in rural areas for their hides, putting the species under some pressure. Coupled with their attractiveness to herptoculturists, many populations of these species are at risk. They are also considered pests in many places in South America, as they have been known to hunt farm stocks (especially for eggs) and even go so far as begging for food in parks. The latter behaviour has put them in direct conflict with humans, especially since these animals are very powerful and can seriously hurt a human with either a bite or a lash of their tail.

* It should be noted that this taxonomic classification is in some dispute. Some herpetologists claim there should be only three species, others claim as many as six or seven. Until serious genetic work is done, consider this classification as only one of several equiprobable organizations.

** Mad props to JudyT for setting me straight on this. I had previously attributed the etymology to the Portugese.

Information culled from personal experience and the following sources: