Crotalus willardi silus, the Western Chihuahuan ridge-nosed rattlesnake, is a subspecies of ridge-nosed rattlesnake native to Mexico and the USA.

[1] Crotalus willardi silus is recognisable as it has less conspicuous markings than its sister subspecies.

Its head is brown with irregular dark spots, it has a dark ocular band starting dark brown at the corner of the eyes and fades to grey as it reaches the end of the supralabials and the front of the head is usually grey.

[2] Its rattle is dark brown and rounded, with sharp scales as a sheath for it, as is characteristic of the species.

[3] Crotalus willardi silus has been recorded to eat rodents.