Black rat snake, Pilot snake, Pilot black snake, Chicken snake; in Florida: Yellow rat snake, Everglades rat snake
The Eastern rat snake is a nonvenomous snake native to North America. Adults are shiny black dorsally, with a cream or white chin and throat. Their belly has an irregular black and white checkerboard pattern, becoming uniformly slate gray towards the tail. Juveniles have dark dorsal blotches on a grayish ground color. The ventral pattern in juveniles is the same as in adults. The eyes are round with a black pupil, and particularly in juveniles but not always present in adults, a distinct white margin. Males and females have the same coloration.
Eastern rat snakes are found in the United States east of the Apalachicola River in Florida, east of the Chattahoochee River in Georgia, east of the Appalachian Mountains, north to southeastern New York and western Vermont, eastern Pennsylvania, Maryland, South Carolina, North Carolina, Georgia, south to the Florida Keys. These snakes live in a variety of habitats. These include farmlands, hardwood forests, forested wetlands, thickets and fields adjacent to forests, isolated urban woodlots and backyards that support populations of prey species. Eastern rat snakes can even get into human residences, where they may live in attics undetected.
Eastern rat snakes are primarily active at night during the summer, and diurnal in the spring and fall. They are terrestrial burrowers and excellent climbers, and they may enter the water. Eastern rat snakes find their shelter under rocks and boards, and in trees under bark and within knot holes and palm fronds. They hibernate during the winter underground or in deep crevices. They are generally solitary creatures but may congregate in the same dens with other species of snakes, such as copperheads, Eastern racers, and Timber rattlesnakes. In Northern climes, Eastern rat snakes are active from late April to October and mate in May or June. In the South, they usually become active earlier. Ratsnakes are most vulnerable to predators as juveniles although adults also have few known predators other than humans. When frightened, Eastern rat snakes will freeze. If harassed, they will produce a foul-smelling musk to deter predators. If provoked further, they may coil, shake their tail, and snap at their attacker.
Eastern rat snakes are carnivorous reptiles. Their diet includes rodents, lizards, frogs, birds and their eggs. These snakes can also eat young chickens and chicks, hence the common name chicken snake.
Eastern rat snakes start to breed in May and June, earlier in the South. Males approach females to initiate breeding and may combat other males before breeding. About five weeks after mating, the female lays 5 to 27 eggs in hollow standing and fallen trees, compost and mulch heaps, sawdust piles, and decomposing logs. Incubation is about two months, and eggs hatch from July through September. Hatchlings are usually just over a foot long at birth, with the distinct gray and black pattern characteristic of juveniles. They are able to care for themselves upon hatching and reach reproductive maturity in their fourth year.
There are no major threats to Eastern rat snakes at present. However, these snakes are often killed because of fear. Their habitat is slowly being reduced locally due to agricultural development and urbanization but in most areas, Eastern rat snakes continue to maintain a healthy population.
According to IUCN, the Eastern rat snake is locally common and widespread throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.
Eastern rat snakes play a very important role in their ecosystem as due to their diet habit they control populations of various pests such as mice, rats, and other rodents.