How to Identify the Arizona Black Rattlesnake (Identification Guide)
The Arizona Black Rattlesnake is identified by its dark, often nearly solid black or blackish-brown body, an unusual trait among rattlesnakes, found in the mountains of central Arizona.
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Key identifying features
The Arizona Black Rattlesnake (Crotalus cerberus) is a medium-sized rattlesnake distinguished by its unusually dark coloration, ranging from deep olive-black to nearly solid black in mature adults, a trait uncommon among North American rattlesnakes. This darkening pattern, combined with its montane habitat, makes it fairly straightforward to identify within its limited range.
Coloration & pattern
Juveniles typically show a more visible pattern of dark blotches or bands on a lighter brown, gray, or yellowish background, similar to other western rattlesnakes. As individuals mature, melanin increases substantially, and adults often become dark olive, blackish-brown, or nearly jet black, with the original blotched pattern becoming faint or nearly invisible except in certain lighting. This ontogenetic darkening is a hallmark trait of the species.
Head, eyes & scales
The head is broad and triangular, typical of pit vipers, with vertical pupils and heat-sensing pits between the eye and nostril. In darker adults, head markings are often obscured by the overall blackish coloration. Scales are keeled.
Size & body shape
Adults typically range from 30 to 42 inches, with a moderately heavy body. The tail carries a segmented rattle, and overall proportions are consistent with other members of the western rattlesnake group.
Range & habitat where you'll see it
The Arizona Black Rattlesnake is found in the mountainous regions of central and eastern Arizona, including the Mogollon Rim and surrounding highland areas, typically at elevations between 5,000 and 8,000 feet. It favors pine and mixed conifer forest, meadows, and rocky outcrops in these cooler, higher-elevation habitats compared to most other Arizona rattlesnakes.
How to tell it apart from look-alikes
The Black-tailed Rattlesnake shares a dark tail but retains a lighter olive or tan body with clear diamond blotches, unlike the often nearly all-black body of the Arizona Black Rattlesnake. Other Arizona rattlesnakes such as the Western Diamond-backed Rattlesnake maintain much more visible patterning throughout life. The tendency toward near-uniform dark coloration in mature adults, combined with a preference for higher-elevation pine forest habitat, is the most reliable way to identify the Arizona Black Rattlesnake.
Frequently asked questions
Why is the Arizona Black Rattlesnake so dark?
It develops increased melanin as it matures, causing adults to become dark olive to nearly solid black, obscuring the blotched juvenile pattern.
Do young Arizona Black Rattlesnakes look different from adults?
Yes, juveniles show a more visible blotched pattern on a lighter background, which darkens substantially as the snake matures.
Where does the Arizona Black Rattlesnake live?
It is found in mountainous central and eastern Arizona, particularly around the Mogollon Rim, at elevations of 5,000 to 8,000 feet in pine forest habitat.
How can the Arizona Black Rattlesnake be told apart from the Black-tailed Rattlesnake?
The Black-tailed Rattlesnake retains a lighter olive or tan body with clear diamond blotches, while the Arizona Black Rattlesnake often becomes nearly uniformly dark overall.
How large does the Arizona Black Rattlesnake grow?
Adults typically range from 30 to 42 inches in length.