Northern Pacific Rattlesnake / Crotale de l'Ouest
The Northern Pacific Rattlesnake is a moderately large, heavy-bodied snake with a
distinctly triangular head and a rattle at the end of the tail. The eyes have vertical
pupils. It is a tan or brownish snake with large brownish irregular blotches down the
back and smaller blotches along the sides. The blotches are often lighter in the
centre, dark at the edges but surrounded with a light border. Maximum adult size is
over 1.6 m.
Although there are no other species of rattlesnake in British Columbia, there are other
blotched snakes which are commonly mistaken for rattlesnakes. The
Great Basin Gophersnake tends to have a
more regular checkered pattern to the blotches.
Night Snakes, found in British Columbia, also have vertical pupils but are much
smaller and more slender than Northern Pacific Rattlesnakes. Neither of these species
has the typical triangular head and rattle of a rattlesnake.
Northern Pacific Rattlesnakes are found in interior British Columbia and adjacent
states as far south as central California.
The Northern Pacific Rattlesnake is found in desert, short grass prairie and dry open
scrubland. It is often seen near rock piles or boulders in areas with sandy soil but
may also be found near farms and fields. This snake may also be found on rocky outcrops
and talus slopes and in association with Prairie Dog towns.
Females begin breeding at an age of 6-8 years and probably do not breed every year.
They are live bearing and produce 4-21 young up to 30 cm long. Young are born in late
summer or fall.
Rattlesnakes have heat sensing facial pits which allow them to locate warm blooded
prey such as small mammals and birds. Farmers value them in reducing pests. They also
eat reptiles and amphibians. They often hibernate communally in rock crevices or
caves or individually in mammal burrows. In spring they may be seen basking at the
entrance to a communal
They are an aggressive snake and when disturbed will coil, vibrate the rattle and strike.
Although bites are rarely fatal Northern Pacific Rattlesnakes are venomous and should be
treated with caution.
Their communal denning habit makes this snake particularly vulnerable to persecution by
people. The Northern Pacific Rattlesnake has been designated Threatened by
COSEWIC because of its limited
distribution in Canada, and the rapid loss of its habitat through urbanization and