Photo credit:

Eric Centenero Alcala

Common name

Chihuahua Ridgenosed Rattlesnake

Scientific name

Crotalus willardi silus

Conservation Status

Least Concern

Federal and State Protections

Federally Protected (MX)

Range Map


Countries of Occurrence

Mexico, US

Adult size

15in (38cm) - 19.6in (50cm)

States or Providence 

Sonora (MX), Chihuahua (MX), New Mexico (US)


Species Description

The Chihuahua Ridgenosed Rattlesnake is a small species of rattlesnake found in the northern parts of the Sierra Madre Occidental mountains in Mexico and a small region of the Animas Mountains in the US. It has the largest range of any C. willardi subspecies. They favor temperate pine-oak forests with streams or creek-beds, and are most active during the rainy season. This species is found at elevations of 5500 to 8000ft (1676 -2438m) above sea level.

A generalist predator, this species targets a wide variety of prey, including lizards, rodents and even centipedes.