Reptiles
Twin-Spotted Rattlesnake
Crotalus pricei · also called twin-spotted rattlesnakes
High atop an isolated Arizona sky island, surrounded on all sides by desert too hot and dry for it to ever cross, a twin-spotted rattlesnake moves quietly through cool coniferous forest, cut off from every other population of its own species by nothing but elevation and temperature.
Overview
The twin-spotted rattlesnake, Crotalus pricei, is a small venomous snake restricted to isolated sky island mountain ranges across southeastern Arizona, southwestern New Mexico, and adjacent Mexico. Its unusual high-elevation forest habitat and genuinely isolated island-like distribution make it one of the more geographically distinctive rattlesnake species in North America.
A rattlesnake stranded on a mountain in the sky
While most rattlesnakes are creatures of open desert, the twin-spotted rattlesnake has adapted to cool, forested mountaintops instead, each isolated peak holding its own separate population unable to reach any of the others across the surrounding desert.
Status
Least Concern — present across suitable high-elevation sky island habitat, though its isolated distribution leaves individual mountain populations more vulnerable to disturbance.
Twin-Spotted Rattlesnake: common questions
What is a sky island, and why does the twin-spotted rattlesnake live on one?
A sky island is an isolated, forested high-elevation mountain range surrounded by lower, much hotter desert terrain that acts as a barrier the twin-spotted rattlesnake cannot cross, meaning each mountain range's population is effectively cut off from others, a genuinely isolated distribution unusual among rattlesnake species generally.
Why does the twin-spotted rattlesnake live in cool forest instead of the desert?
A twin-spotted rattlesnake occupies cool, moist coniferous forest habitat at high elevation, an environment quite different from the hot, dry desert many other rattlesnake species prefer, an adaptation that allows the species to exploit a genuinely different ecological niche within the broader desert region it is surrounded by.
How small is the twin-spotted rattlesnake?
The twin-spotted rattlesnake ranks among the smallest rattlesnake species found in the United States, considerably smaller than many of its larger, more widely known rattlesnake relatives such as the timber rattlesnake or the diamondback rattlesnakes.
Where does the twin-spotted rattlesnake live?
The twin-spotted rattlesnake is native to isolated sky island mountain ranges across southeastern Arizona, southwestern New Mexico, and adjacent parts of Mexico, restricted specifically to cool, high-elevation coniferous forest habitat on these isolated peaks.