The Gray Rat Snake (Elaphe obsoleta spiloides) is a member of the genus Elaphe in the colubrine subfamily Colubrinae. Within the genus Elaphe, which includes Rat snakes, Corn snakes, and Fox snakes, the Gray rat snake is one of five subspecies, or races, of the nominate Black rat snake (E. o. obsoleta). The subspecies of Elaphe obsoleta include: the Black rat snake, Gray rat snake, Yellow rat snake (E. o. quadrivittata), Everglades rat snake (E. o. rossalleni), and the Texas rat snake (E. o. lindheimeri)
A medium to large serpent, gray rat snakes typically reach an adult size of 39" to 72" (3.25-6 feet), however, the record is 84.5"(7.041 ft.) Unlike other Elaphe obsoleta whose conspicuous juvenile pattern fades into adulthood, gray rat snakes do not undergo drastic ontogenetic changes in color, or markings. These snakes retain the juvenile pattern of dark elongate dorsal blotches separated by four, or more, pale gray body scales, a light gray crown with dark striping that forms an anteriorly facing spearpoint, and a solid band which covers the eyes and extends rearward to the posterior upper labial scales. The venter is usually off-white or pale gray with darker irregular blotches, and a double row of black spots behind the divided anal plate of the vent. The dorsal scale rows around midbody are usually weakly keeled. Because the gray rat snake shares its range with other members of its species, intergrades of black/gray and yellow/gray rat snakes are not uncommon.
A common snake of the Southeastern US, gray rat snakes inhabit many urban and rural environs within a range that includes the FL panhandle, southern and western GA, all of AL, and MS, north to western TN and along the eastern Mississippi River valley to St. Louis.
An agile climber, gray rat snakes are at home from the ground to the tree tops in many types of hardwood forest and cypress stands, along tree-lined streams and fields, and even barns and sheds in close proximity to people. Within its range, almost any environment rich in rodents, and vertical escape options, proves a suitable habitat for the gray rat snake. As scent-hunters these powerful constrictors feed primarily on rodents, and bird and their eggs as adults, while neonates and juveniles prefer a vertebrate diet of frogs and lizards. When startled, this species, like other rat snakes, stops and remains motionless with its body held in a series of wave-like kinks. The gray rat snake will defend itself by raising its head and bluffing a strike. If handled, these snakes will musk a victim by releasing the foul-smelling contents of their cloaca, and will bite if necessary. However, the gray rat snake is less likely to bite than other members of its species, and wounds from a bite rarely reqire more than a bandage. Breeding takes place from April to July. Females deposit 5 to 27 eggs around mid-summer, and the 10" to 12" hatchlings usually emerge in September.
It should be noted that while a taxonomic suggestion has been made to change the genus Elaphe to Pantherophis, and this suggestion has been taken up by the web community at large, most herpetologists do not accept the suggestion and Herpetological Review 2003 34(3) rejected the taxonomic change. One argument against the change is that the Russian study that suggested it was based on mitochondrial DNA evidence, not nuclear DNA and thus no relevance to the reproductive and nuclear genetic relatedness of the genera can be inferred from the data.
The gray rat snake is considered common and is not listed as a protected species by any states within its range. However, in the state of Georgia, all indigenous, nonvenomous snakes are illegal to kill or capture, and are considered to be in the custody of the Georgia Department of Natural Resources.