Reptiles
Ridge-Nosed Rattlesnake
Crotalus willardi · also called ridge-nosed rattlesnakes
High within a forested sky island mountain range in southeastern Arizona, a ridge-nosed rattlesnake moves quietly through leaf litter, one of the smallest rattlesnakes in the United States and a species found almost nowhere else, isolated on a scattering of mountain peaks surrounded by desert it cannot cross.
Overview
The ridge-nosed rattlesnake, Crotalus willardi, is a small, venomous pit viper native to forested mountain sky island habitat across southeastern Arizona, southwestern New Mexico, and northern Mexico. Its distinctive raised snout ridge, restriction to isolated mountain sky islands, and status as the official state reptile of Arizona make it one of the more geographically specific and visually distinctive rattlesnakes in North America.
A rattlesnake stranded on its own mountain
Separated from other populations by desert lowland it cannot survive crossing, each ridge-nosed rattlesnake population remains confined to its own isolated forested mountain, a sky-island existence shared by several other specialised species across the same region.
Status
Least Concern — present across suitable forested mountain sky island habitat within its naturally restricted range.
Ridge-Nosed Rattlesnake: common questions
Why is it called the ridge-nosed rattlesnake?
This species has a distinctive raised ridge running along each side of the snout, a physical feature clearly visible on close inspection that sets it apart from other rattlesnake species and gives the species its descriptive common name.
Why is the ridge-nosed rattlesnake found only on certain mountains?
This species is restricted to a handful of isolated, forested mountain ranges known as sky islands, each surrounded by inhospitable desert lowland the species cannot cross or survive in, meaning each mountain's population has effectively been isolated from the others for a very long time.
Is the ridge-nosed rattlesnake dangerous?
While this species is venomous like all rattlesnakes, it is notably small, among the smallest rattlesnake species found within the United States, and generally considered less aggressive than several larger relatives, typically relying on camouflage and stillness rather than an immediate defensive strike when encountered.
Why is the ridge-nosed rattlesnake the state reptile of Arizona?
This species was designated the official state reptile of Arizona in recognition of its close association with the state's forested mountain sky island habitat, being found within the United States almost exclusively in Arizona's mountains aside from a small adjoining area of New Mexico, making it a fitting and geographically specific state symbol.