According to a 1977 report by Bruce Bury and later work by Geoff Hammerson, the McElmo Natural Area and its immediate surroundings contain 13 species of snakes, lizards and amphibians, with at least another six species possible. This makes it one of the richest areas in the state for these animals. This fact alone would make the site significant. In Colorado it is known only from the Four Corners area and parts of the lower Arkansas River drainage. The snake's skin has white bands or stripes on a black body.
Adults are usually two feet long.
The kingsnake is an aggressive predator, preying on rodents, birds, eggs and other reptiles, including lizards, rattlesnakes and bull snakes. The desert spiny lizard is known in Colorado only from the Four Corners. This lizard prefers semi-arid shrublands or grassy plains near drainages. This diurnal lizard is very wary and will flee into hiding when threatened. It forages for insects, smaller lizards, and tender vegetation.