Argentine Black & White Tegu

  • Common Group: MONITORS & TEGUS
  • Common Name: Argentine Black & White Tegu
  • Scientific Name: Tupinambis merianae
  • Distribution: Argentina, S. America
  • **Size: 3' - 4.5'

Natural History

The giant black and white tegus of South America are among the most intelligent and highly adapted of all living lizards. They typically inhabit forest-edge savannahs and adjacent rain forests of Argentina and parts of Brazil and Uruguay. They are largely terrestrial, and spend copious amounts of time in deep burrows which afford protection from dehydration and extreme temperatures.

As pets, tegus can be one of the most rewarding of the large lizards to keep. Their moderate size, attractive appearance, and cat-like demeanor have quickly propelled them into the herpetecultural spotlight.

Size and Longevity

Tegus are fast growing lizards, often reaching sexual maturity in 3 years or less. Males grow larger, sometimes exceeding 4 feet in total length with a thick, muscular build. Females are slightly smaller, usually in the 3 foot range, and are more slightly built than their male counterparts.

Life spans of 15 years or more can be expected with this species given that close attention is paid to diet and other basic husbandry considerations.


Hatchling black and white tegus are rarely over 8 inches in length and can be comfortably kept in a 30 gallon terrarium for the first months of their lives. As they grow, they will need continually larger enclosures allowing for proper exercise, burrowing activities, and thermoregulation. Young animals can be housed communally ,but monitor them closely for food-related aggression and for size discrepancies.

A single adult male should be provided with an enclosure having a footprint of no less than 6 feet by 2 feet. Pairs may be housed in a slightly larger enclosure (6 feet by 3 or 4 feet), although separation may be required if breeding season aggression occurs. Single females require less space than adult males. Tegus are active and should be given as much space as possible. Closet or room sized enclosures should not be considered out of the question.

Secure, well ventilated enclosures that allow for deep substrate are highly recommended, although tegus are very adaptable, and have done well in a variety of creative housing situations.

Heating and Lighting

As a tropical species, tegus will require warm temperatures during most of the year unless they are being brumated (cooled) for reproductive cycling. Ambient temperatures withing the cage should be between 80 and 90 degrees during the day. Temperatures 5 to 10 degrees cooler are acceptable at night. During daylight hours, a basking spot should be available and should reach 95 to 100 degrees.

Heat can be provided using under tank heat pads, standard and nocturnal (red) heat bulbs, and ceramic heat emitters. The use of a high quality thermometer, preferably one on each end of the cage, is highly recommended.

Although tegus in the wild spend a lot of time in the shelter of burrows, they do bask regularly in the sun, which serves as a source of heat and consequently as a source of ultraviolet light. In captivity the use of a full spectrum UV light is essential for long term health of your lizards. These may be standard fluorescent UV bulbs, or a self-ballasted mercury vapor bulb (such as Zoo Med’s PowerSun) which will double as a source of heat and ultraviolet light.

Substrate and Furnishings

Bark or mulch type beddings are recommended for tegus. Orchid bark, cypress mulch, and coconut husk products are all acceptable. The substrate should be deep as to allow for burrowing and as a means for maintaining adequate humidity.

Tegus tend to rearrange their enclosure to their liking, so elaborately decorated or planted enclosures are not only unnecessary but impractical as well. Instead, provide a few hide spots such as half logs or cork bark slabs.

Water and Humidity

Tegus of all sizes and ages should be provided with a large, sturdy water bowl. Ideally, this receptacle should be large enough to allow for complete submersion of the lizard.

In captivity, humidity levels between 60% and 80% are ideal. This can be achieved via the use of humidity promoting substrates and regular misting of the enclosure with room temperature water. It is not always easy or necessary to maintain these humidity levels within the entire enclosure. Instead, many keepers utilize "humid hides," that is micro-habitats within the enclosure where higher humidity levels are present. The simplest way to accomplish this is by stuffing one or two of your tegus favorite hides with damp sphagnum moss. This moss should be kept slightly more moist than the rest of the bedding, and should be closely monitored for cleanliness.

If kept too dry, or without humid hides, tegus are prone to shedding problems, most notably with the skin of the toes and tail. If such issues present themselves, it is a good indication that more humidity is needed, and more frequent mistings are typically a sufficient fix.


Tegus are typically considered omnivores, although many captive diets do not reflect this tendency. In addition to an assortment of appropriately sized insects (crickets, mealworms, waxworms, roaches), various high calcium fruits should be regularly offered. Willingness to accept fruits will vary from animal to animal, but even a small amount can add a lot of variety and essential nutrients to the tegu diet.

Rodents may be offered, though sparingly, as they tend to be high in fat, and tegus are simply not designed to digest large quantities of fur. Instead, a balanced dietary supplement can be created using raw, ground turkey, whole eggs (with shell), and bone meal or an equivalent calcium/vitamin supplement. This mixture has been widely used by zoos and hobbyists and can safely constitute up 75% of the tegu diet.

Tegus grow quickly and have very active metabolisms. As such, regular feeding is necessary. There is no rule of thumb as to exactly how much to offer, but tegus should have a filled-out appearance when they are full. Start by offering young tegus food daily (as much as they will consume in about an hour), and adjust quantity and frequency as needed.

Calcium and vitamin supplementation is especially important for young tegus. A high quality calcium supplement complete with vitamin D3 should be lightly dusted on all food items. A multivitamin is also highly recommended, and should be added to food at least once a week, less frequently if the diet is exceptionally varied.


One of the major draws to owning tegus is their typically calm demeanor and ease of handling. Babies should be handled regularly from an early age to ensure proper adjustment to human presence. Argentine tegus rarely bite, but more often will squirm about in your hands. Tegus are very smart, and even this behavior will go away with time as they begin to trust you. Avoid hand feeding, as the last thing you want is a hungry tegu that associates any part of your body with food!

© LLLReptile & Supply, Inc 2006