Visitors to Big Bend NP most frequently see the whiptail, earless, and spiny lizards. These slender creatures will often be heard but not seen as they scurry through the vegetation off the side of a trail. Those that are sighted are fast and hide easily. The largest lizards in the park are the Collared (Crotaphytus) and Leopard (Gambelia) lizards which can measure over a foot in total length. Both eat other lizards, insects, spiders, and small snakes.The largest Texas horned lizard (Phrynosoma cornutum) ever recorded was found in Big Bend National Park. Texas horned lizards are not abundant in the park, and in the few places where they are located, they are not found in large numbers. However, there is no evidence that suggests this is abnormal. It is more likely that Big Bend National Park doesn't have enough of the proper type of habitat necessary for these lizards. The main, and often only food for the Texas horned lizard is the harvester ant (Pogonomyrmex) which feeds mostly on grass seed. It is possible, if at one time there were larger grasslands in the Big Bend, there may have been a larger harvester ant population and thus a greater number of Texas horned lizards.
Last updated: April 12, 2020