Central ratsnake

The central ratsnake (Pantherophis alleghaniensis), also commonly known as the black ratsnake, gray ratsnake, chicken snake, midland ratsnake, or pilot black snake, is a species of nonvenomous snake in the subfamily Colubrinae of the family Colubridae. Unlike other Pantherophis, whose conspicuous juvenile pattern fades into adulthood, the gray ratsnake in the southern part of its range does not undergo drastic ontogenetic changes in color or markings. Instead, it retains 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. However, in the northern part of its range it is black in adulthood, like P. quadrivittatus (yellow ratsnake) and P. obsoletus (western ratsnake). 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.

Geographic distribution and habitat

Native to North America, Pantherophis alleghaniensis is commonly found in the forests of the eastern and central United States, west of the Appalachian Mountains and east of the Mississippi River. It occurs relatively continuously throughout the major part of the eastern half of the United States, along the Piedmont throughout Kentucky, from southwestern New England to the Gulf of Mexico, westward to the Mississippi River, and northward from northern Louisiana to southwestern Wisconsin.

In Canada, this species is known to occur in two disjunct regions of southern Ontario: the Carolinian forest region along the north shore of Lake Erie in the southwest, and the Great Lakes/St. Lawrence region in the southeast.

Habitat

An agile climber, These snakes have a large home range that is variable in size based on habitat type and quality. They display site fidelity choosing to return to the same spots within in their range over and over again to hunt.Central ratsnakes frequently live in environments that burn semi-regularly either naturally or as a management technique. The snakes typically return to the habitat within three years of a burn.

thumb|Pantherophis alleghaniensis displaying its ability to climb trees.

Diet and behavior

Diet

A scent-hunter and a powerful constrictor, Pantherophis alleghaniensis feeds primarily on small mammals, birds, and bird eggs.

Behavior

When startled, the central ratsnake, like other ratsnakes, stops and remains motionless with its body held in a series of wave-like kinks. The snake will also rattle its tail against whatever it is lying on, making an audible buzzing sound; this is intended to fool a potential threat into thinking that it has encountered a rattlesnake. The central ratsnake will defend itself by raising its head and bluffing a strike. If handled, it will musk a victim by releasing the foul-smelling contents of its cloaca, and will bite if necessary. However, the central ratsnake is less likely to bite than other members of its genus, and wounds from a bite rarely require more than a small bandage. These snakes are timid and avoid unnecessary conflict, some studies suggest that the stress from capture and restraint is as physiologically demanding as intensive breeding displays. Central ratsnakes are preyed upon by kingsnakes. Kingsnakes are smaller but have a stronger constriction ability than ratsnakes and are able to overpower the ratsnakes.

Reproduction

Breeding in P. alleghaniensis takes place from April to July. Females reach sexual maturity at 7–9 years of age. Additionally, they frequently use communal nesting sites, where multiple females deposit eggs under the same log or stump.

Conservation status

The central ratsnake is considered common across much of its range, but is listed as "of special concern" in Michigan and is also listed as rare in Wisconsin. The central ratsnake is listed federally in Canada as "endangered" (Carolinean population) and "threatened" (Great Lakes – St. Lawrence population).

Habitat destruction and road mortality are leading causes of decline.