Photo credit:

Rob Schell

Common name

Mexican West-Coast Rattlesnake

Scientific name

Crotalus basiliscus

Conservation Status

Least Concern

Federal and State Protections

Range Map


Countries of Occurrence


Adult size

31.7in (80.5cm) - 80.3in (204cm)

States or Providence 

Sonora, Sinaloa, Nayarit, Jalisco, Colima, Michoacan, Oaxaca


Species Description

The Mexican west-coast rattlesnake is a large-bodied snake found between the Gulf of California and the central cordillera. This species typically inhabits dry, lowland thornscrub forests, tropical deciduous forests, and occasionally mixed pine-oak highland forests.

Females of this species give live birth to upwards of 60 young, although the reported average is 33 babies per litter. Infant and juvenile Mexican west-coast rattlesnakes have also been observed climbing into bushes as a means of thermoregulation (controlling their body temperature).

Hybridization with the closely related species, Crotalus molossus, is likely in areas of Sonora where the two species overlap in range.