Western Black-tailed Rattlesnake

Western Black-tailed Rattlesnake

Crotalus molossus

Silhouette: Bill Bouton (source photo) & T. Michael Keesey (vectorization) · PhyloPic

Least ConcernNear ThreatenedVulnerableEndangeredCritically Endangered
Daily sighting probability Insufficient data
at Grand Canyon National Park
2 Verified sightings at Grand Canyon National Park From 2019 to 2026
181 Verified sightings across all 2 parks From 2019 to 2026
☀️🌙 Day & Night When it's spotted Active throughout day and night

About the Western Black-tailed Rattlesnake

The black-tailed rattlesnake (Crotalus molossus) is a venomous pit viper species found in the southwestern United States and Mexico. Four subspecies are currently recognized, including the nominate subspecies described here.

A 2012 revision showed that eastern populations from Texas and central and eastern New Mexico form a distinct species separate from C. molossus: Crotalus ornatus Hallowell 1854. Alternate common names are green rattler, and Northern black-tailed rattlesnake.

This medium-sized species averages from 76 to 107 cm (30 to 42 in) in length. Large specimens are usually not much more than 100 cm (39 in) long, although lengths of 125.0 cm (49.2 in) (Gloyd, 1940), 125.7 cm (49.5 in) (Klauber, 1972), and 129.5 cm (51.0 in) (Shaw & Campbell, 1974) have been reported. The females tend to be larger than the males.

They range in color from yellows and olive greens to browns and black. As their name implies, one of their most distinguishing features is, despite variations in body color, entirely black tail scales. Often, this rattlesnake has a black band across its eyes extending diagonally down to the corners of its mouth... Wikipedia →

Global Distribution

Warmer areas are where this animal is recorded most often.

Parks Where Found

# Park Country Daily sighting probability
1 Saguaro National Park 🇺🇸 United States
~10%
2 Reserva de la Biosfera Mariposa Monarca 🇲🇽 Mexico
Insufficient data
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