Crotalus molossus
Black-tailed Rattlesnake

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Other Names: Black-tailed Rattlesnake, Green Rattler
Subspecies: Northern Black-tailed Rattlesnake Crotalus molossus molossus
Description: A large 22"- 48" rattlesnake that may be brown, gray, yellow-brown, or straw colored with a series of large, black or brown, blotches on the back. The blotches are jagged-edged. A few light patches mark the interior of each dorsal blotch. The blotches are eight sided with thin lined running down the sides to the belly. On the posterior part of the body the blotches become narrow, muted crossbands. The pupils are vertical and the dorsal scales are keeled. The neck is slender and the head is wide and triangular. The body color gradually fades in to a solid black tail.
Similar Species: The easiest way to tell the two species of Blacktails in New Mexico apart is the connection of the anterior blotches dorsolaterally in the Eastern Blacktail. The anterior blotches in the Northern Blacktail tend to remain separate along the sides. The solid-colored black or dark brown tail and the light scales within the dark body blotches should distinguish this from other rattlesnakes in New Mexico.
Venom: Venomous
Habitat: This snake is found at low regions up to 8,000'. It is found in a wide variety of Desertscrub to lower Conifer Forest. It seems to be most abundant in the woodlands. It is almost always found above the flats in hilly or mountainous terrain.
Behavior: Is diurnal but can be crepuscular in spring and fall and becomes nocturnal during the hot summer months. Usually a calm snake.
Hibernation: Hibernates in deep cracks. Known to communal den with Western Diamondbacks (C. atrox) and Rock Rattlesnakes (C. lepidis)
Reproduction: Gives live birth.
Diet: It feeds on mice, rats, rabbits, other small mammals, birds, and lizards.
Authored by: Garth Teitjen