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 . Young are usually born or hatch in late summer or early fall. Egg or embryo development ranges from eight to 12 months. Reproduction in ovoviviparous species such as the timber rattlesnake first occurs at three to seven years after birth.