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This site was created by students in the herpetology class at Towson University. Site last updated: 05/21/07.
Acknowledgements: Herb Harris - Range Maps; Mark Tegges - Photography; Dan Lapascha & Gigi Forester - TU Herpetology Logo
Eastern Ratsnake
(Pantherophis alleghaniensis)
Description
A mid-sized snake, the adult black rat snake ranges in length from 42-72 inches. Scales are keeled, the anal plate is divided, and there are 29 or fewer scale rows at mid-body. The dorsum is black, and the throat and neck are white or yellowish. In contrast to the black racer, Coluber constrictor, in which white is restricted only to the throat, the venter of the black rat snake is a mixture of light and dark blotches. Juveniles are gray with black splotches running mid-dorsally.
Habitat
Black rat snakes are good climbers, and often spend time in trees, rocky ledges, and abandoned buildings. They tend to live near or in woodlands, often by water. In spring and fall, black rat snakes often bask on rocks or in other open areas. Adults eat small mammals, while juveniles eat frogs, lizards, birds, bird eggs, and small mammals.
Breeding
Mating occurs a few weeks after leaving hibernation in spring. Males attract females with pheromones, and then the male will wrap his tail around the female's in order to insert one of his hemipenes into her cloaca. In mid-summer, the female lays between 5 and 22 eggs under a hollow log, rocks, or leaves. The eggs will hatch 65-70 days later, and hatchlings average 12 inches in length. If conditions are ideal, a female may lay 2 clutches in one year.
Distribution in Maryland
Range map adapted from Harris, 1975.
Links
http://animaldiversity.ummz.umich.edu/site/accounts/information/Elaphe_obsoleta.html
http://museum.nhm.uga.edu/gawildlife/reptiles/squamata/serpentes/colubridae/eobsoleta.html
http://www.michigan.gov/dnr/0,1607,7-153-10370_12145_12201-61209--,00.html
http://www.umass.edu/nrec/snake_pit/pages/brat.html