Rattled by Rattlesnakes?

Have you been walking in the Foothills and thought you heard castanets? There’s a good chance it was a rattlesnake’s cautionary tail.

Rattlesnakes are venomous snakes in the pit viper subfamily. Their genus, Crotalus (from Greek krótalοn), means “rattle" or “castanet”, a reference to their tail. Native across America, from Canada to Argentina, most rattler species live in the American Southwest and Mexico. Seven rattlesnake species live in Utah; the Great Basin rattler inhabits the SLC Foothills.

Frequently people mistake the Great Basin Gopher Snake for the rattler because they have similar markings—pale brown, tan or grey with darker blotches down their backs and sides—but they are easily distinguished. Rattlers have large, triangular-shaped heads with the heat-sensing pits located between their eyes and nostrils. The gopher snake’s head is narrow and bullet-shaped. The rattler’s body is thick with flat sloping sides; the gopher snake’s is rounded and slender. And rattlers have the tell-tale rattle, evolved to scare danger away. The distinctive loud buzz is the sound of its tail flicking up to 90 times/second. No other terrestrial vertebrate can twitch their muscles this fast, twice the speed of a hovering hummingbird’s wing!

Rattlesnakes are ambush predators, holding their rattle up to stay quiet while moving so as not to alert unsuspecting prey. Using highly specialized thermal “vision”, vibration detection, and sensitive smell, they strike their target, injecting venom through long hollow fangs that swing forward and down when they bite.

The best way to stay safe in rattlesnake country is to stay alert. If you hear or see a rattlesnake, be deferential; give it space and leave. Remember they want nothing to do with you. And rattlers are predictable. If feeling threatened they coil protectively, striking only when they can’t escape or scare you away. Only 30%-40% of bites envenomate; rattlers don’t want to waste venom for defense.

Rattlesnakes are protected in Utah. Unfortunately they are threatened by habitat loss, poaching and extermination campaigns, despite playing a vital role in predator-prey balance. When you meet a rattlesnake, consider how fortunate you are to glimpse this beautifully evolved reptile in its home. And always remain respectful.

By Hilary Jacobs

Great Basin Gopher Snake — Similar markings to a Rattlesnake, they have a narrow head

Rattlesnake getting ready to strike