● Venomous · Native to Arizona and New Mexico

Arizona black rattlesnake

Crotalus cerberus (Coues, 1875)

Data updated October 2026

Dark Arizona black rattlesnake coiled on rocks, showing thin pale crossbars on a nearly black body
Fig. 1 — Adult on rocks, nearly black with thin pale crossbars.
Lighter young Arizona black rattlesnake with brown blotches on a gray body
Fig. 2 — Young snakes are gray with brown blotches and darken as they age.

At a glance

A dark rattlesnake of Arizona’s mountains and the edge of western New Mexico, living in canyons, woodland and pine forest near water. It darkens with age, can shift its shade, and is known for complex social behavior, including mothers staying with newborn young.

01

Identification

The Arizona black rattlesnake is a medium-to-large pit viper with a broad triangular head and a slender neck. Young snakes are light gray with brown blotches and facial markings, and they darken gradually as they age. Many adults look almost solid black, with thin crossbars of white, yellow or orange, while others keep dark blotches on a gray-brown background. Adults can also lighten or darken their color, a trait that is unusual among Arizona’s snakes. It was long treated as a form of the western rattlesnake, but physical, habitat and genetic differences led researchers to treat it as a separate species.

  1. 01Dark color. Adults are blackish, unlike the tan to reddish adults of related western rattlesnakes.
  2. 02Thin pale crossbars. Narrow white, yellow or orange bars cross the dark back of many adults.
  3. 03Pit viper features. Heat-sensing pits between eyes and nostrils, a triangular head and a rattle.

02

Size

01 ft2 ft3 ft4 ft Large adult · about 42 in (107 cm)

This is a medium-to-large rattlesnake. The largest measured about 42 inches (1,062 mm), not counting the rattle. Young are much smaller and paler than adults.

03

Range & habitat

Rocky canyon with pine and oak trees along a mountain stream in central Arizona
Fig. 3 — Wooded canyons with rocky drainages and water nearby.

Arizona black rattlesnakes are found only in Arizona and extreme west-central New Mexico. They range through the mountains of central Arizona from south of the Grand Canyon across and below the Mogollon Rim and the White Mountains, and south into the Santa Catalina and Rincon mountains near Tucson. They live at about 4,000 to over 9,000 ft, in semidesert grassland, woodland, shrubland and montane conifer forest. They favor cooler, moister spots with dense plant cover and are closely tied to springs, streams and rocky drainages, though they also use open, rocky slopes. They are most common at the highest elevations of Saguaro National Park and rare at the lower elevations of Tonto National Monument.

04

Diet & predators

Arizona black rattlesnakes hunt mostly from ambush, often lying beside fallen logs and other woody debris. They use their heat-sensing pits to find prey and subdue it with venom delivered through long, hollow fangs. They eat rodents, lizards and birds.

Feeds on

  • Rodents
  • Lizards
  • Birds

Preyed on by

  • Natural predators are poorly documented
  • Wildfire and habitat loss (main threat)
Mouse on the forest floor
Prey — rodents.
Spiny lizard on a rock
Prey — lizards.

05

Behavior & seasons

Arizona black rattlesnakes live on the ground and are active mostly by day, though they can be out at other times when conditions are right. They avoid trails and other developed areas but may cross them to reach cover. Researchers have described complex social interactions in this species, including parental care.

Near Tonto National Monument they are active from late March through early October and hibernate from late October through March, about two months less than near Flagstaff. At high elevations they rely on communal dens and birthing sites in large rock outcrops and rocky talus slopes, though some hibernate alone. At lower elevations they appear to use rocky drainages instead.

06

Reproduction

Arizona black rattlesnakes give birth to live young. Mating takes place in late summer and fall, during the summer rains. During courtship a male may coil completely on top of a female, a behavior called “stacking.” Females appear to have about four or five young per litter, born in summer, often around August. Mothers appear to stay with their young until the babies first shed their skin, about one to two weeks after birth.

07

Conservation

The Arizona black rattlesnake is ranked secure, is locally common in places, and receives no special state or federal protection. In Arizona, however, it may not be taken from Mingus Mountain in Yavapai County or from parts of Graham County. Researchers flag it as a species of concern because of climate change: hotter, drier conditions, forest pests and wildfires are expected to shrink its pine and pinyon-juniper habitat, and one study projected a 32% to 46% loss of its occupied range by 2099, mostly at lower elevations.

08 — Bite safety

If someone is bitten

Arizona black rattlesnake bites are medically serious, and every bite needs medical care. Call 911 or go to the nearest emergency department. For guidance, call Poison Control at 1-800-222-1222. If a pet is bitten, take it to a veterinarian right away.

This page does not give first-aid or treatment instructions. Read our safety disclaimer.

Keep reading

Sources

Data updated October 2026 · How we build these pages