NNTRC Snakes

Scientific Name

Crotalus molossus

Common Name 

Blacktail rattlesnake

Physical Characteristics

Length, (70-125 cm). The ground color can vary from cream, yellow, grey, and olive green to dark rust. The dorsal pattern consists of several dark somewhat diamond shaped marks. The head has a dark colored snout with dark eye stripes that passes diagonally toward the corners of the mouth. The tail is usually black but can be dark grey with vague slightly lighter colored rings. Uniformly dark almost melanistic individuals can be common in some areas.

Geographic Range (USA & Mexico)

North west Arizona across to central New Mexico, over to the Edwards Plateau area in central Texas and southward through the Mexican states of Sonora, Chihuahua, and eastern and southern Caohuila.

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A predominantly montaine snake that inhabits outcrops, streams, and rockslides. Can be found from sea level to 3000 m.


small mammals


Hemorrhagic toxins resulting in tissue damage and edema


Blacktail rattlesnakes are usually not aggressive unless agitated. However, large adults can deliver a fair amount of venom in a bite so they should be considered dangerous.

This page was last updated on: February 12, 2016