Species Spotlight: Gray Ratsnake
Common name: Gray Ratsnake (also known as Eastern Ratsnake or Black Ratsnake)
The Gray Ratsnake, sometimes called the Eastern Ratsnake or Black Ratsnake, is Canada's largest snake, reaching a length of up to 190 cm. Their colouring differs from region to region, but they are generally a shiny black or gray with a white chin and throat.
In Canada, this snake is only found in two distinct parts of Ontario: the Carolinian forest region of Lake Erie, and the St. Lawrence region in counties such as Lanark, Leeds and Grenville, and Frontenac. They range in the United States through the eastern and central parts of the country. The Gray Ratsnake lives in a variety of environments from open, grassy fields, enclosed spaces such as rock crevices and under logs, to basking up on tree branches.
The Gray Ratsnake is a constrictor, mainly preying on small mammals and, since it is an efficient arboreal hunter, birds and their nests. Its natural predators include Red-tailed Hawk, Osprey, Raccoon, Fisher and Mink.
Major threats to the species include being run over by vehicles - given their length and tendency to move slowly across roadways – or agricultural machinery, deliberate slaughter by humans and habitat loss due to increased development.
This snake can live up to 25 to 30 years, but due to the species' tendency to only lay clutches of 10 to 15 eggs late in their life cycle every two or three years, even small threats to the Gray Ratsnake have major implications for its overall survival.
What is Being Done
The species is protected provincially under Ontario's Fish and Wildlife Conservation Act and Endangered Species Act. Both populations of the Gray Ratsnake are protected under the Species at Risk Act, and the Great Lakes/St. Lawrence population is also protected under the National Parks Act, as it is commonly found in the St. Lawrence Islands National Park.
One of the key measures identified for this species' conservation is identification and protection of their hibernacula.
What You Can Do
Ontario's Biodiversity: Species at Risk – Eastern Ratsnake
Committee on the Status of Endangered Wildlife in Canada, COSEWIC
Species at Risk Public Registry, SARA
Thanks to Nature Canada volunteer Michael Berrigan for contributing this profile.