This ground-dwelling species inhabits a variety of habitats such as tropical rainforest Yungas forest, flooded forest, savanna, and river and sea banks. It is found both in forest and open situations, frequently seen near water. It can be adapted to several disturbed situations such as gardens , road edges, and rural towns, and urban and suburban areas. A heliothermic, wide-ranging lizard, it searches actively for its food. At night, and when seeking refuge during the day, it retreats into burrows in the ground. Diet is variable, and includes plants (leaves and fruits) and a wide range of animals, from arthropods to frogs, lizards, small birds and mammals, and their eggs. It may also act as a scavenger. It is predated by hawks such as Buteo nitidus. It is an egg-laying species (Duellman 1978, Avila-Pires 1995). 

On Trinidad and Tobago it seems to avoid heavily urbanized areas and primary forest, but may be found in edge situation of both. It occurs in secondary forest, mangrove, wet savanna, riparian forests, abandoned fields, littoral vegetation near beaches, old pasture with numerous oil rigs (J.C. Murphy pers, comm. 2015).

Trinidadian folklore (Everard and Boos, 1975) states that the young hatch during thunder storms, this suggests Beebe’s (1945) observations of females depositing eggs in termite nests is correct for Tupinambis cryptus sp. n., and likely correct for other members of the T. teguixin group. Females excavate a chamber in a termite nest (often in arboreal situations), deposit their eggs, and the termites re-seal the nest chamber. The eggs hatch and the hatchlings escape when the termite nest softens during heavy rains. When disturbed their first defence response is to escape into vegetation or a burrow, but if cornered they raise their body and posture with stiffened legs while hissing and threating with an open mouth. They will drop their tails and we have found shed tails in the field.

This species occurs in northern South America (Trinidad and Tobago. French Guiana, Suriname, Guyana, Venezuela, Colombia, Ecuador, Peru, Bolivia, and Brazil), extending southward through gallery forests to the state of Sao Paulo, Brazil (Avila-Pires 1995). On Trinidad and Tobago it is widespread and occurs from sea level to at least 600 m.

Currently, this species is of relatively low conservation concern and does not require significant additional protection, management, or monitoring. It occurs in several protected areas, including most on Trinidad and Tobago. However, there are no limits on hunters taking as many as they can find on Trinidad and Tobago.

Tegu lizards in general are important in Neotropical ecosystems as predators, scavengers (Schneider et al. 2011), and seed dispersal agents (Beebe 1945). They are also hunted for skins and meat by thousands of indigenous and local peoples, and are important sources of protein and income (Fitzgerald et al. 1996). Tegus make up 1−5 % of the biomass harvested (Hill and Padwe 1983, Rumiz et al. 2001) by the local populations studied. However modest the indigenous harvest may appear, the actual numbers in trade suggest Tupinambis are being harvested at a dramatic rate. Fitzgerald (2012) reports 34 million in trade during the three decades between 1977 and 2006, where the primary end product was cowboy boots. Tupinambis are to varying degrees habitat generalists using forests as well as savannas, climbing trees, burrowing, and using aquatic habitats; and their populations must be, or were, substantial to sustain an annual harvest that averages 1.4 million individuals per year for thirty years.
This species is listed in CITES Appendix II.