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Arizona Black Rattlesnake vs Western Rattlesnake
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(c) tzeducation, some rights reserved (CC BY)
Arizona Black Rattlesnake
Crotalus cerberus
Venomous(c) Yan Davidovich, some rights reserved (CC BY-SA)
Western Rattlesnake
Crotalus oreganus
VenomousThe quick way to tell
Look at the body color and blotches. An adult Arizona Black Rattlesnake is very dark, often nearly black, with blotches that fade into the background. The Western Rattlesnake is usually tan to reddish with clear blotches.
Pattern ★ This settles it
25 to 46 dark blotches down the back, separated by lighter gaps. On dark adults the blotches can almost disappear into the dark background.
Pale-edged blotches wider than long, banding near the tail; olive to nearly black.
Head
A wide, triangular rattlesnake head. Young snakes have bold spots on the head and a dark bar running back from the eye; these fade as the snake darkens with age.
Broad triangular head with a dark cheek stripe bordered by white.
Eyes
Vertical, cat-like pupils, as in other rattlesnakes. A dark bar runs back from each eye, most easily seen on young snakes.
Vertical slit pupil; heat-sensing pit between eye and nostril.
Pits
Yes. It has a heat-sensing pit on each side of the head between the eye and the nostril, like all rattlesnakes.
A deep heat-sensing pit on each side of the face, between the eye and the nostril.
Tail
Ends in a rattle. The body blotches turn into dark bands on the tail, and these bands fade as the snake gets older.
Thin ahead of the rattle.
What it does
Often calm compared with other rattlesnakes. It is social: groups share winter dens, bask together in spring, and mothers stay with their newborn young for about one to two weeks.
Coils and rattles; retreats to rocks if given room.
Where it lives
Central Arizona, from the Mogollon Rim south to mountain ranges near Tucson, and west-central New Mexico. Mostly found at about 2,800–9,150 ft (853–2,789 m).
Pacific states and the Great Basin: Washington, Oregon, Idaho, California, Nevada, Utah and Arizona, east into western Colorado and southwestern Wyoming, plus British Columbia and Baja California.