Overview
The Twin-spotted Rattlesnake (Crotalus pricei) is a diminutive, cold-tolerant montane rattlesnake isolated atop the famous ‘sky island’ mountain ranges of the North American Southwest and northern Mexico. Named for the charming parallel rows of paired dark brown spots that march down its back, this docile mountain specialist thrives at elevations where winter freezes linger and summer temperatures remain cool.
Biology and Physical Characteristics
Measuring rarely more than two feet in length, Crotalus pricei features a blue-gray, pearl-gray, or brownish background coloration punctuated by 39 to 64 pairs of rounded dark-brown dorsal spots. Its small rattle produces a high-frequency buzzing sound often mistaken for a buzzing grasshopper. Unlike desert pit vipers, it is adapted for cold alpine microclimates, actively basking on exposed quartzite rocks during brief sunny intervals to regulate metabolic digestion.
Behavior and Ecology
Exclusively diurnal, the Twin-spotted Rattlesnake spends much of its active season patrolling rocky talus slides and lichen-encrusted boulder fields in search of its primary prey: montane lizards like the Mountain Spiny Lizard (Sceloporus jarrovii). It retreats deep into subalpine rock fissures to escape nocturnal sub-freezing temperatures and spends up to seven months hibernating underground during long montane winters.
Conservation and Human Impact
Classified as Least Concern by the IUCN, Crotalus pricei enjoys stable populations within protected sky island wilderness areas like the Chiricahua and Huachuca mountains. However, because its habitat is strictly restricted to high elevations, climate-induced warming and increased catastrophic wildfire severity threaten the Douglas-fir and pine-oak forest canopies that shade its talus refuges.
Interesting Factoid
Because its high-elevation habitat cools down rapidly when clouds pass over, the Twin-spotted Rattlesnake can flatten its ribcage horizontally like a pancake to absorb maximum solar warmth in seconds.
Last updated: October 2026