Ancient Alligators

Texas Alligator Lizard

An ancient and widespread lizard family, Anguidae originated in the Triassic Period, over 100 million years ago.  Today there are 67 species recognized worldwide, with 8 found in North and Central America. Members of a large branch of the snake/lizard evolutionary tree that use their strong jaws rather than tongues to draw food into the mouth, Anguids reserve their hard, slightly forked tongues as chemosensory organs used to search for food, mates, and safe refuge.  

One subfamily within this group is called the alligator lizards, so named due to a vague resemblance to an alligator – a flat, wedge-shaped head, little neck definition, small, thin legs, and scales fairly large and shingled that barely overlap one another. These lizards shed in one piece, much like a snake, turning the old skin inside out as they crawl out of it.  They can also exhibit tail autonomy, the ability to shed their tail as a self-defense mechanism to elude a predator’s grasp and allow escape. While they have the ability to regrow their tail over a period of weeks or months, the new tail is often shorter and distinctly different in appearance from the original tail.

The only species of alligator lizard in Texas is the Texas Alligator Lizard (Gerrhonotus infernalis). Males have wider, more triangular heads than females, but both can grow up to 18 inches long, including their tail. Ground color ranges from light tan to dark brown, sometimes with a reddish cast, with 7 to 10 black and white flecked bands across the body. Newly hatched individuals look entirely different than the adults, with striking copper-colored heads and boldly banded black and cream bodies that resemble centipedes or millipedes.

Generally preferring moist areas of foothills to lowland limestone canyons, staying near springs, creeks, and streams, the Texas Alligator Lizard can even be found in suburban areas near these habitats.  They feed primarily on insects, spiders, and small vertebrates. However, they are secretive in nature, hiding under surface cover such as fallen tree limbs, forest undergrowth, and in rocky crevices.  They can be pugnacious when caught, often thrashing about and able to deliver a painful bite. When threatened by a predator, they may flee to water as they are good swimmers, or perform lateral undulation by folding in their thin limbs and slithering away quickly like a snake.   

Depending on the temperature or season, Texas Alligator Lizards may be active by day or night. In spring they are often arboreal as their tails are prehensile and assist in climbing, mating and feeding in vine tangles and other dense vegetation up to 9 feet off the ground.  Fall is mating season, with males fighting each other for the right to court a female.  Eggs are laid in clutches of 5 to 31 under rocks and in crevices between February and June, with females producing a second clutch if conditions are favorable. Unlike many other reptile species, females will remain with their clutch of eggs for the few months it takes them to incubate.

Texas Alligator Lizards are found throughout a few disjunct localities in the Big Bend region and in much of the Edwards Plateau, and are the largest limbed lizards in Texas. While their secretive nature means they often go undetected, it is a special treat to discover and observe one of these ancient alligators!