The Sidewinder Rattlesnake

Desert Life in the San Felipe region


The Sidewinder is a rattlesnake that is highly adapted to the desert conditions. Another accepted common name is the Horned Rattlesnake. There are three identifiable varieties of Sidewinders found in the southwestern deserts of North America. San Felipe is located in the Colorado Desert and the local subspecies is appropriately named the Colorado Desert Sidewinder. The scientific name is Crotalus cerastes laterorepens.

The sand dunes surrounding San Felipe makes it ideal as a domain for the sidewinder. It gets its name because of the side winding motion that it employs when attempting to maneuver across the very loose sand, although it is very capable of typical snake locomotion also. Other snakes that encounter loose sand would have to turn away as they cannot maneuver due to lack of traction. The sand tracks that Sidewinders leave resemble the letter “J” which makes it easy to determine the direction in which the snake was headed. The curved or lower part of the letter is made by the head so that curve is pointing to the snake’s travel direction. The photo below showing the track illustrates this very well. This picture was taken just south of San Felipe close to the airport.


Although sidewinders are primarily nocturnal, they may be found out in the daytime usually coiled under a bush in wait for their favorite food, lizards. They will eat rodents also but the prey would have to be small. Sidewinders are very small snakes. An 18 inch Sidewinder is considered an average size. A Sidewinder that is two feet long is a very large example.

A lie-in-wait Sidewinder buries itself in the sand with its head about the level of the sand surface. Only its horned head sticks up. Why the horns is a mystery. Some speculate that they help deflect sand that may blow by its head during a sand storm. Others say that the horns help protect the eye as they snake goes down a hole. The snake cannot close its eyes for protection as they have no eyelids. If fact, no snake has eyelids. This fact makes it easy to differentiate between a snake and a legless lizard.

The venom is not considered to be very potent. In fact, I know of no human deaths from a Sidewinder bite. The venom appears to have evolved mostly to subdue lizards. Typically, the snake will strike at a passing lizard and hold onto the lizard in its mouth while injecting the venom. As with all snakes, the snake has many smaller teeth that are curved backwards or towards the snakes throat. This makes it difficult for the prey to escape. The harder the prey fights, the deeper the teeth can penetrate.


David Spiteri is a retired professor of biology with Herpetology as his specialty. He is a desert lover who lives both in the high Mojave Desert of Southern California and also in the Sonoran Desert of Arizona. He owns property in San Felipe and plans to combine both beach and desert exploration in the near future.