The Argentine black and white tegu (Salvator merianae), also known as the Argentine giant tegu, the black and white tegu, or the huge tegu, is a species of lizard in the family Teiidae. The species is the largest of the "tegu lizards". It is an omnivorous species which inhabits the tropical rain forests, savannas and semi-deserts of eastern and central South America.
Tegus are sometimes kept as pets by humans. They are notable for their unusually high intelligence and can also be housebroken. Like other reptiles, tegus go into brumation in autumn when the temperature drops. They exhibit a high level of activity during their wakeful period of the year. They are the only known extant non-avian reptiles to be partly endothermic.
Tegus fill ecological niches similar to those of monitor lizards, but are only distantly related to them; the similarities are an example of convergent evolution.
Etymology
The Argentine black and white tegu is of the Order Squamata and Family Teiidae, which also includes racerunners and whiptails. There are nine total genera of tegu, though new taxonomic classifications change, with the Argentine black and white tegu being of the Salvator genus. The specific name, merianae, is in honor of German-born naturalist Maria Sibylla Merian, a naturalist and artist who studied insects, plants, and reptiles from the 17th to the 18th centuries.
Description
As a hatchling, Salvator merianae has an emerald green color from the tip of its snout to midway down its neck, with black markings. The emerald green becomes black several months after shedding. As a young tegu, the tail is banded yellow and black; as it ages, the solid yellow bands nearest to the body change to areas of weak speckling. Fewer solid bands indicates an older animal. A tegu can drop a section of its tail as a distraction if attacked. The tail is also used as a weapon to swipe at an aggressor; even a half-hearted swipe can leave a bruise.
Tegus are capable of running at high speeds and can run bipedally for short distances. They often use this method in territorial defense, with the mouth open and front legs held wide to look more threatening.
Adult males are much larger than the females and can reach in length at maturity. They may continue to grow to lengths of .
The females are much smaller, but may grow up to in length from nose to tail. They have beaded skin and stripes running down their bodies. Adult females can reach a weight of .
The skull is heavily built with a large facial process of the maxilla, a single premaxilla, paired nasals, a single frontal bone and two parietal bones separated by the sagittal suture. Biomechanical analyses suggest the posterior processes of the parietal might be important for dealing with torsional loads due to posterior biting on one side. In the large adults, the posterior teeth are larger and more rounded than the anterior teeth.
Sex
When a tegu reaches the age of 8 months, the beginning of their juvenile age, their sex can easily be determined visually; their vent at the base of the tail will bulge when it is a male and lie flat when it is a female. Breeders generally inform the buyer on the sex of the animal before the purchase. In adults, the main difference is in the jowls; adult males have substantially developed jowls (a result of hypertrophic lateral pterygoideus muscles), while females' jawlines are more streamlined.
Ecology
Distribution and habitat
As the name would suggest, this tegu is native to Argentina, but also to Brazil, Paraguay and Uruguay.
Salvator merianae (once known as Tupinambis merianae) aka the Argentine Black and White Tegu is a large reptile native to South America. There are significant populations of Argentine Black and White Tegus in the southern United States and the Brazilian coast. They are a consistently problematic invasive species in Florida counties, most likely as a result of escaped or released species from the early 2000s pet trade. Previous studies have found that the differing weather and climate patterns far outside of their natural habitat range do not prevent adult Argentine Black and White Tegus from surviving in diverse areas across the United States, furthering concerns about their invasive status. In the wild, tegus inhabit both forested and open plain environments, widening their potential invasive range.
Tegus have also been found in scrub and wet habitats such as flooded savannas, canals, ponds, and streams. They largely seem indiscriminate of habitat type as long as they have the ability to burrow.