The prairie rattlesnake is an ancient inhabitant of the high plains and valleys of Wyoming and is common in the eastern two-thirds of the state except in alpine habitats. These pit vipers use heat-sensing facial pits to detect warm-bodied prey. During winter they hibernate in underground dens for up to eight months, then in spring they migrate away from the dens in search of food, typically rodents and other small mammals, and mates. Studies show they travel from the den in a virtually straight-line path for several miles until they find a food source, using the sun as a navigational aid, and when temperatures cool in fall they return to the same den. Though poisonous and seemingly hostile, they present virtually no chance of biting unless touched, provoked, or frightened. Because rattlesnakes are deaf and cannot actually hear rattling, that behavior is believed to be defensive, warning off creatures they perceive as threats. As a secretive reptilian hunter that has lived in this area for thousands and thousands of years, the prairie rattlesnake is a fascinating and important element of Wyoming’s wildlands.