is carried out by Jacobson's organ in the palate. To stimulate Jacobson's organ, they use their tongues to transport air and ground molecules to Jacobson's organ. Then, the organ analyzes the molecules to identify the scent. Among these detectable scents are pheromones, which indicate the presence of other snakes and their reproductive readiness. Lifecycle and behavior The lifespan of Elaphe spp. is generally 15 years. Males live a little longer than females, but some species, such as E. guttata (now considered Pantherophis guttata), live up to 23 years in captivity. However, species such as E. emoryi (now considered Pantherophis emoryi) usually have lifespans around 2 years and 2 months. Elaphe spp. generally reach sexual maturity after 18–24 months. They usually mate with the opposite sex after emerging from hibernation in the spring. The gestation period of females is around 1.5 months, and females can lay up to 30 eggs in a clutch, the number varying between species. E. guttata and E. obsoleta, among others, are mostly diurnal, but some species are more active in late afternoon or at dusk. Throughout the year, they are usually active from April to October, followed by a period of hibernation. Hibernation Elaphe spp. hibernate, especially those that live in cold regions, because snakes are cold-blooded, which makes their body temperature susceptible to the temperature of their environments. Thus, they need to maintain their body energy by switching locations and remaining physiologically inactive when winter comes. The hibernacula sites vary depending on the habitats they live in, yet the most important requirement of a hibernaculum site is that it needs to be frost-free. Some Elaphe spp. hibernate in the rock crevices, rock faults, and burrows. However, other species choose to hibernate in rotting logs, roots of trees, and hollow spaces in elevated tree trunks. Some snakes that live close to human communities even hibernate in old wells and barns. Most members of the genus Elaphe start their hibernation in October and emerge again the next spring. The length of the hibernation varies by species. Elaphe longissima, or Aesculapian snake, may hibernate from October to May, as it is among the northernmost occurring rat snakes. However, Elaphe bimaculata, or the twin-spotted rat snake, only needs to hibernate for 2 to 3 months. Species such as black rat snakes, or E. obsoleta, hibernate with other rat snakes and/or many other snake species, most notably timber rattlesnakes, racers,