​Keeping and Breeding the Argentine Black and White Tegu

By Bert Langerwerf of AGAMA

Sientific differences between Argentine and Columbian tegus

The differences discussed below apply to Argentine Black & White tegus and all Columbian tegus. Thus with "Columbian tegu" I mean any tegu coming from Columbia, and with "Argentine tegu" I mean the Argentine Black & White tegu. Now let's talk about the scientific name of this tegu. It used to be called Tupinambis teguixin until not too long ago. But their new name is Tupinambis merianae. The Columbian tegus are now called Tupinambis teguixin. There is a definite biological difference between these two species. One difference, among many, is that the Argentine tegu, T. merianae, has two loreal scales while the Columbian tegu, T. teguixin, has only one (see diagram below). The Argentine Black & White tegu is also called the giant tegu, as it is the largest tegu in the world.

Also easily observed is the difference in skin types. The Argentine Black & White tegu has a beaded skin, like that of a gila monster or an anolis. The Columbian tegus have very smooth scales that completely cover the animal. The Columbian tegus are smooth, like a skink almost. The Argentine Black & White tegus also have two linear arrays of yellow dots, one on each side of its back, running from the neck to the beginning of the tail . Those yellow dots form two clearly visible lines on the Argentine tegu's back. The Columbian tegus lack such lines. A non-scientific way to tell a Columbian tegu from an Argentine Black & White tegu is by knowing the purchasing price of the tegu you are looking at. If the price is around $100 or less (most likely $50), than you have a Columbian tegu. Also, by probability theory, the odds of seeing a Columbian tegu are much higher than the odds of seeing an Argentine tegu, simply because the Argentine tegu is much rarer and impossible to export from Argentina.

Our Argentine tegus are the largest tegus of South America, reaching more than four feet in length. Having kept in captivity both the Argentine and Colombian tegus, I can say that the Argentine tegus are also less jumpy than the Colombian ones. Furthermore, the Argentine Giant tegus are cold tolerant and can even be placed in hibernation. Thus no expensive heating devices are needed to keep the Argentine Giant tegu healthy in captivity; they can be kept outside in many places. A very important thing to note is that these Argentine Giant tegus are very intelligent and thus also much more easily tamed than Columbian tegus. Important too is the fact that our Argentine tegus do not only eat meat as the Colombian tegus do, but also a lot of fruits, vegetables, cat-foods, and breads. If your tegu does not eat anything besides meat products, it is most likely a Columbian tegu of some sort.​

 Tameness of these tegus

If your goal is to get a tame tegu we recommend that you start out with a young tegu as those are most easily tamed. It has been found that the Argentine tegus (T. merianae and T. rufescens) are the most tamable of all tegus in the world. We also have a few Columbian tegus (Tupinambis teguixin) kept inside. But even though they see us every day they keep being jumpy and frequently slam their tails on the glass or into the water bowl making a big mess. Our Argentine B/W tegus we also see daily, but they are never afraid of us or anybody else visiting our place. They either stay where they are, sleeping or basking, or come closer to you sticking their tongues out to investigate. This suggests that they are the tamer tegus of South America. Furthermore, Bert went to Argentina to film the tegus there and had no problem photographing them in the wild. They even were in some city parks. There are plenty of stories going around about Argentine Black & White Tegus stealing fish bait AND lunch from fishermen! Bert also witnessed the tegus in the park begging for food from picnickers, just like squirrels do in New York or L.A., for example. Our good friend Dick Bartlett (author of many Barron herp books) told us that he had the greatest difficulties photographing any of the Columbian tegus when he was in Columbia. He could not approach them at all, as the Columbian tegus ran away once they got a glimpse of him (or anybody else). Thus under similar circumstances, both in nature and in captivity, the Columbian tegus behave more frightened of humans and are therefore far less tame than the Argentine tegus. That is why we believe that the Argentine Black & White Tegus are the most tamable tegus of the world!

Range and Climate

In 1989, I received my first group of Argentine black and white tegus. Comparing the temperate climate in Argentina with the climate in Alabama, where I now live, I felt that Argentine tegus could be kept and bred here outdoors. The key would be to design large outdoor terraria in such a way that the microclimate would be similar to the one found where these lizards naturally occur.

The southern-most point of its range in Argentina is 41"S latitude. Outside the country of Argentina, this lizard occurs in portions of Uruguay and Brazil.

The Argentine black and white tegu is a versatile lizard. It ranges from tropical Amazonia south to more temperate regions that have moderate temperatures and cold winters. I chose to try to duplicate the climate of Victoria in the mid-north of the province of La Pampa, at 36"13'S and 65"26'W. This region of Argentina is temperate, and it is also home to the red tegu (T. rufescens).

In the county of Uruguay, the Argentine black and white tegu lives in stony meadows, river valleys and in the mountains. Both Dr. F. Achaval and Dr. J. Cei state that this tegu is an excellent swimmer, and that, if threatened, it can stay under water for a long time.

Diet of the Argentine Black & White tegu

According to Achaval (1977), its food consists mainly of insects, snails, bird eggs, fruits, and vegetables. Dr. Cei (1986) writes that this lizard eats birds, small mammals, insects, mollusks, fish, amphibians, and fruit. Claudia Mercolli and Alberto Yanosky describe the food more extensively in the Journal of the British Herpetocultural Society (1994, vol. 4). They examined the stomach contents of 70 Argentine black and white tegus (bought from hide-hunters) in northeastern Argentina. They found that 66.8 % of the stomach contents consisted of vegetable matter; 12.9 % were invertebrates; and 20.3 % were vertebrates. This stands in contrast to what herpetoculturists tend to feed their tegus: almost 100% rodents and eggs. Dr. Fred Frye (1981) warns that the overuse of infertile bird eggs, such as readily available chicken eggs, can result in a lack of biotin.

Hibernation of these tegus

These tegus can hibernate. The life cycle of the Argentine black and white tegu in my outdoor enclosure has been extremely interesting to observe. In the middle of August, when it is still hot here in Alabama, they start to refuse food and begin preparing their burrows for hibernation. They tend to all dig and prepare one large sleeping chamber. In the middle of September, they are all inside that chamber despite temperatures of 80 to 90 F during the day. The tegus close the burrow from the inside with earth. Any time during the winter when I open this to check it, they closed it again with earth afterwards. They stay in this burrow or chamber for 6 months to emerge again, covered by dirt and mud, in mid-March. It is not until April that they resume feeding. They have a 4 month activity burst in April, May, June, and July. During this time, they eat all they can find and catch.

Reproduction

The first reproduction I observed with captives of this species was at 3 years of age. The sub adult female produces about 36 eggs, which hatch after 3 months under natural conditions. The neonate Argentine tegus were shiny green and about 3.1 inches in SVL (snout vent length) and 7.8 inches in TL (total length).

The average SVL of the hatchlings was 3.5 inches, and average TL was 9.3 inches. In the first two months of life, young Argentine tegus exhibit an interesting behavior. If caught and handled, their tail starts vibrating in a manner not unlike that of some colubrid snakes. My juvenile Argentine black and white tegus regularly accept crickets, mealworms, and pinkie mice. They grow quite quickly in outdoor vivaria with exposure to natural sunlight in Alabama. At 19 days after hatching they start shedding their skin and their green color begins to fade. At 1 month of age, the green color is almost gone. At 32 days old, the length of one was 5.1 inch SVL and 14.6 inch TL. At 2 months of age, one tegu was 5.8 inch SVL and 16.3 inch TL and weighed 5 oz. (142 gram).

Nest building observed only in Argentine Black & White tegus

In May 1995, I observed a gravid female busily moving material to its nesting site. In 30 years of breeding lizards of many different families, I have never before observed a lizard using nesting material not already in the nest hole. These lizards were making nests as crocodilians do!

This Care Sheet was Supplied By Agama International