Rattlesnakes hibernate through the winter in communal burrows. For the Great Basin Rattlesnakes, mating occurs between March and May and sometimes in the fall. Young are live-born, usually between August and October in litter sizes of 4 - 21 young. The record lifespan of a Great Basin Rattlesnake is 19 ½ years. Rattlesnakes are 'sit and wait' predators. Instead of hunting, they prefer to hide and let prey come to them. Rattlesnakes sense their surrounding world in several ways. With forward facing eyes, their vision is more binocular than that of most snakes. This gives them excellent aim and the ability to precisely judge distances when striking. They also can 'smell' by collecting molecules on their forked tongues, then transferring them to a special receptor on the roof of their mouth called the Jacobson's Organ. (A snake's nostrils serve no olfactory function whatsoever; they are used only for respiration.)