Description
The Common Garter Snake is highly variable in colour
but tends to be black with three stripes: one down the back and one
on each side. The stripes are usually yellow. The side stripes
are confined to the second and third scale rows. The subspecies
commonly found in western Canada is the Red-sided Garter Snake
which has red or orange markings between the stripes. The Common
Garter Snake can grow to over a meter in length.
Confusing Species
Depending upon the area, the Common Garter Snake can be
confused with different species. In British Columbia, there are
two other garter snakes. The Western
Terrestrial Garter Snake has a black stripe, but has dark
spots. The Northwestern Garter
Snake can
be quite similar, but is generally brown, rather than black. From
Alberta to Manitoba, the other confusing species is the Plains Garter Snake, but it has
squarish black
spots as well as the stripes. In southern Ontario, there is Butler's Garter Snake which looks
very
similar, but the side stripes are on the second, third and fourth
scale rows. There is also the Ribbon
Snake, which is quite similar to the Common Garter Snake. Its
side stripes are only on the third and fourth scale rows.
Distribution
The Common Garter Snake is the most widely distributed
reptile in Canada -- it is found in every province, with the
exception of Newfoundland, as well as the southern part of the
Northwest Territories. It occurs across almost all of the US, with
the exception of the driest areas in the southwest.
Habitat
The Common Garter Snake is found in a wide variety of
habitats from forests to farmlands. It also occurs in many urban
areas. It is usually found near wetlands of some sort.
Reproduction
Breeding generally occurs in the spring, soon after
emerging from hibernation, but it can also occur in the fall. In
some areas, it is possible to see many snakes involved in mating
frenzies near hibernation sites. Females typically give birth to
10-30 live young in mid-summer. Up to 85 young have been reported
from one female! The young are 13-23 cm at birth and mature in 2-3
years.
Natural history
The Common Garter Snake is the most commonly
encountered snake in most parts of its range. It has adapted well
to human modification of the landscape. It is active during the
day and is commonly seen in moist areas where it hunts frogs,
toads, salamanders and earthworms. Small fish and mice are also
eaten. The Common Garter Snake hibernates underground in burrows,
rock outcroppings, or the foundations of old buildings. In some
areas, hundreds or even thousands of snakes will hibernate in the
same location.
Conservation Concerns
The Common Garter Snake is widespread and abundant in
Canada. Aside from loss of wetlands, the greatest threat to this
snake is likely traffic mortality. Many snakes are drawn to warm
roads in the evening and are killed by passing cars.
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