Description
The Rat Snake is the largest snake in Canada, growing
to 2.5 m in total length. It has three different basic colour
patterns, but the subspecies found in Canada, the Black Rat Snake,
is quite constant in colour. It is plain black, although there may
be some white between the scales. The belly is usually whitish
with black markings.
Confusing Species
The large size and dark colouration of the Rat Snake
can only be confused with the Northern Water
Snake, which is generally patterned, but gets darker with age.
The belly of the Northern Water Snake is also whitish, but with
dark crescent-shaped spots.
Distribution
The Rat Snake is limited to southern Ontario in Canada.
It is found in two disjunct areas: the north shore of Lake Erie and
the eastern end of Lake Ontario. To the south, the Rat Snake is
found across most of the eastern US as far south as northern
Mexico.
Habitat
Rat Snakes prefer wooded areas although they may spend
part of the summer in open areas such as old fields or meadows.
Reproduction
Breeding occurs in spring and the females lay their
eggs in rotting logs or under rocks. Up to 24 eggs can be laid,
but 12-16 is more common. The eggs hatch in late summer or early
fall. The hatchlings are 30-40 cm long.
Natural history
The sight of a 2 m snake draped across the branches of
a tree is not expected in Canada, but the Rat Snake does
frequently make use of trees. It regularly climbs trees to eat
birds' eggs or nestlings. In addition to birds, it also eats small
mammals and frogs. In eastern Ontario Rat Snakes hibernate
communally in rocky outcrops.
Conservation Concerns
Because of their large size Rat Snakes are frequently
killed by insensitive people who dislike, or fear snakes. They are
also killed on roads. The small size of their range in Canada also
makes them vulnerable to further decline. They are designated
Threatened in Canada by COSEWIC.
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