Conservation of Endangered Species in Canada: Gray Ratsnake Endangered Species Profile



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Species Spotlight: Gray Ratsnake

Gray Ratsnake
©John C. Murphy/
www.jcmnaturalhistory.com

Vital Signs

Common name: Gray Ratsnake (also known as Eastern Ratsnake or Black Ratsnake)
Latin name: Pantherophis spiloides
Status under SARA: Threatened, Endangered
Range: In Canada, two distinct Ontario regions: Great Lakes/St. Lawrence (southeast) and Carolinian forest (southwest)
Life span: 25 to 30 years
Size: Males can reach a maximum length of 190 cm
Population estimate: Great Lakes/St. Lawrence population between 25,000 and 85,000 (as of 2002)

The Story

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.

The Facts

	Females begin nesting in early July and August, and often use communal sites frequented by other members of the species.
	The Gray Ratsnake's active season extends from the middle of April to mid October, due to the cold Canadian climate; during the remainder of the year, they hibernate in communal underground sites (hibernacula).
	Adult Gray Ratsnakes are strongly attached to their territory and often return to the same sites from year to year.
	It is one of the Canadian species of snake still being intentionally harmed and killed by humans, despite it being non-venomous.

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

1.	Share what you've learned about the Gray Ratsnake with others. Knowledge helps us to understand our wild neighbours and the natural environments they need to survive.
2.	Stay alert when driving. Wildlife can cross human-made boundaries such as roads in unexpected places, so we need to take care not to endanger the animals or our own safety.
3.	Never intentionally cause harm to snakes or other animals simply out of fear or misunderstanding, as this has major implications for any species' survival.
4.	Stay informed about endangered birds and other species by signing up to Nature Canada's monthly e-newsletter.

Resources:

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.