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Species at Risk

Eastern Ratsnake

Elaphe obsoleta

What is the Eastern Ratsnake?

Species at Risk - Who Knew?

When approached, Eastern Ratsnakes may emit an unpleasant odour or make a rattling sound - even though these snakes do not have rattles!

Adult Eastern Ratsnakes grow to 1.5-1.8 metres long. Although admittedly impressive and somewhat intimidating, they are not venomous.

Adults are most often shiny black with a whitish chin and throat. Juveniles have a blotchy pattern and are paler than adults, becoming darker with age.

Eastern Ratsnakes are good tree climbers. Their diet consists mainly of bird eggs and nestlings, insects and small mammals no larger than a grey squirrel.

The natural predators of ratsnakes include mink, hawks, coyotes and racoons.

In Canada, individual ratsnakes can live as long as 25-30 years. Eastern ratsnakes reproduce at a rather slow rate and, in fact, only reach sexual maturity at 10-12 years of age. Females lay their eggs only every other year.

The species' preferred habitat is woodland edges, where deciduous forest meets open habitat such as fields, clearings and ponds. Ratsnakes are also found in and around abandoned buildings, which provide food and shelter.

Ratsnakes, like all snakes, are cold-blooded animals so many of their habits are geared to finding a suitable temperature. For example:

  • To keep their eggs warm, Eastern Ratsnakes lay their clutch in decaying vegetation or manure piles.
  • To survive the winter, this species gather in underground cavities (hibernacula) below the frost line
  • In the spring and fall in particular, Eastern Ratsnakes look for warm, sunny spots such as tree trunks and roads for basking.

Although these habits are essential to the Eastern Ratsnakes's survival, they can also make the species more vulnerable to certain dangers.

Where are Eastern Ratsnakes found?

Eastern Ratsnake moving among branches on the ground.
The Eastern Ratsnake finds food and shelter in piles of branches on the ground.
© Parks Canada/Sutherland, D./1982

In Canada, the species is found only in Ontario, where there are five remaining populations isolated from one another: