This small rattlesnake can be found in southeastern Arizona and down through Mexico along the Sierra Madre Occidental. In Arizona, it is limited to just four isolated mountains. The twin-spotted rattlesnake primarily feeds on lizards and mammals, but has also been recorded as consuming bird nestlings, and there has been at least one instance of cannibalism. The snakes are most active during their breeding season June-September.

Fun fact: The twin-spotted rattlesnake is named after William Wightman "Billy" Price (1871–1922), a field biologist who studied the natural history of many species during a time of exploration and discovery. He primarily captured birds and mammals across North America for university collections, and he also collected rattlesnakes from Arizona and Mexico. Two fishes, two small mammals, and this rattlesnake are each named after him.