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Photo credit:

Dick Bartlett

Common name

Tamaulipan Rock Rattlesnake

Scientific name

Crotalus morulus

Conservation Status

Federal and State Protections

Range Map


Countries of Occurrence


Adult size

States or Providence 

Tamaulipas, Nuevo-Leon, Coahuila


Species Description

The Tamaulipan rock rattlesnake was only recently elevated to its own species by Bryson et al. 2014. It occupies humid pine-oak forest, cloud forest and agave shrubland in the Sierra Madre Oriental in Mexico between 1,190m (3,900ft) - 2,740m (9,000ft) elevation. Little is known about this rattlesnake's ecology, but its venom is being used in research for future medications.

Its venom is more lethal against invertebrates than lizards or mice, sporting the most specialized anti-invertebrate venom of any of the C. lepidus complex, which implies that its diet is more invertebrate-based (likely centipedes); but more research is needed into its diet and behavior.

Fun fact: In 2016, researchers from universities in the United States, Mexico, and Venezuela were the first to isolate a protein in the venom of the Tamaulipan rock rattlesnake called morulustatin which has implications for future antithrombotic and anticancer drugs.

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