Tegu (Salvator merianae)

ReptileLizardSouth America

Overview

Tegus are large, robust lizards of South America, with powerful limbs, strong jaws, a long tail, and a beaded, often boldly patterned skin. The Argentine black-and-white tegu (Salvator merianae), shown here, is the best-known species — among the largest of all tegus, marked with bands and speckles of black and white. Intelligent and alert, tegus are sometimes compared to monitor lizards in behaviour and are often described as among the more “clever” reptiles.

One species, the Argentine tegu, is remarkable for a trait once thought impossible in lizards: during its breeding season it can keep its body noticeably warmer than its surroundings, a partial, seasonal form of warm-bloodedness.

Note: there are several tegu species; details here use the Argentine black-and-white tegu as a reference. Treat general statements as approximate and verify against authoritative sources.

Habitat & Range

Tegus live across much of South America, from tropical forests and savannas to scrub and the edges of farmland, depending on the species. The Argentine black-and-white tegu favours open and semi-open habitats in central South America, digging burrows for shelter and to escape the heat and cold, and it hibernates (brumates) underground during cooler months.

Diet

Tegus are omnivores with a broad appetite: fruit, seeds, insects, snails, eggs, small vertebrates such as rodents, frogs, and other reptiles, and carrion. The Argentine tegu is notable for raiding nests for eggs, including those of other reptiles and ground-nesting birds. This dietary flexibility helps tegus thrive in many settings — and contributes to their impact where they have been introduced.

Behavior

Tegus are active by day, terrestrial, and good diggers, sheltering in burrows and basking to warm up. They are alert and inquisitive, and the Argentine tegu in particular shows a striking seasonal physiology: in the breeding season it can raise its body temperature several degrees above its surroundings through internal heat production — a partial endothermy unusual among reptiles. When threatened, tegus may inflate the body, hiss, lash with the tail, or bite, but they often flee to a burrow.

Human Interaction & Conservation

Tegus are kept as exotic pets (where legal) and are generally hardy, and the Argentine tegu is widespread in its native range. However, escaped or released pets have established invasive populations in places such as Florida, where they prey on the eggs and young of native wildlife — a serious conservation concern that underlines why exotic pets should never be released. Consult authoritative sources for species-specific and regional status.

More photos of the tegu