Reptiles

Black-Tailed Rattlesnake

Photo by Ron Stewart

Coronado National Memorial supports a moderately diverse herpetofauna of seven amphibian and 36 reptile species. This diversity results from several factors including the fairly large elevation range and location in the overlap zones among the Chihuahuan and Sonoran Deserts, the Rocky Mountains, the Sierra Madre Occidental, and the Great Plains. The upper elevations of the Memorial contain many of the taxa with restricted U.S. ranges associated with the sky islands, including the mountain skink, Yarrow’s spiny lizard, bunch grass lizard, banded rock rattlesnake, Madrean alligator lizard, and Chihuahuan blackhead snake. The unique limestone areas provide rare habitat for barking frogs. Lower elevations include Great Plains species that are near the western limits of their range, such as the western hognose snake, the Texas blind snake, and the ornate box turtle, as well as a few Sonoran Desert species that are close to the eastern limit of their ranges, such as the Gila monster and Sonoran spotted whiptail.

The black-tailed rattlesnake pictured above is a fairly common resident of Coronado National Memorial; their range is the Southwest U.S. into Mexico. It can be distinguished from the more common diamondback rattlesnake by its solid black tail. Its color can vary from yellowish to green, with dark splotches. It may grow to 42 inches long and will live 15-20 years. They use heat sensors (pits) on their faces and chemical detecting organs in their mouths and tongue to hunt. They cannot hear. They use their venomous bite to kill their prey and start digestion. Prey includes small mammals, birds, snakes, lizards, and frogs. Black-tails will hunt during the day in cooler times and at night during the heat of the summer.

Though dangerous, black-tailed rattlesnakes are less aggressive than diamondbacks, relying primarily of their camouflage to avoid predators; bites are rare. They will rattle, hiss, and coil when threatened. Most bites to humans occur when someone tries to handle them or initiates contact. Their venom is less potent than other rattlesnakes and their bites are rarely fatal to humans. A good rule of thumb in the Arizona grasslands and desert is to never put your hands or feet someplace you cannot see first!