Snakes must move into and out of various temperature zones to regulate their bodily functions properly. Basking in the sun is vital to physiological processes such as temperature regulation, digestion and egg development. Snakes do not have limbs that allow them to reach out and touch things, so they need to be able to monitor their environment by some other method. They possess a forked tongue that flicks in and out of the mouth to sample scent molecules. The tongue transfers these molecules to the Jacobsen's organ located on the roof of the mouth.
Chemical information is transferred to the brain, which allows the snake to interpret the smell.
Scent trailing is used in locating prey, finding mates and returning to hibernating areas. Reproduction Mating can occur from spring until fall, depending on the species. Snakes give birth in one of two ways. Species that lay eggs, such as the black rat snake, are termed oviparous . Other species including garter snakes, water snakes, and Pennsylvania's three venomous species give birth to live young and are termed ovoviviparous .