Hypsiglena chlorophaea deserticola
Northern Desert Nightsnake / Couleuvre nocturne
The Nightsnake, and other slender, rear-fanged snakes, which were included within
the Family Colubridae, have recently been placed in the Family Dipsadidae.
The Nightsnake is beige, yellowish or gray with numerous dark brown or gray blotches
on the back and sides. Although it is relatively similar to other blotched snakes,
the Nightsnake has a characteristic large blotch on each side of the neck. The
pupils of the eyes are also vertical. The Nightsnake can grow to over 60 cm in
The Nightsnake is similar to other blotched snakes of British Columbia. The
Wandering Gartersnake has a yellow or brown
stripe down the length of the back. The Great
Basin Gophersnake grows to a much larger size. Small individuals can be confused
with the Nightsnake, but the Gophersnake has a round pupil. The
Northern Pacific Rattlesnake has the same
basic pattern of the Nightsnake, as well as the vertical pupil. It can be
distinguished from the Nightsnake by the presence of the rattle, and the
characteristic triangular head.
The Nightsnake appears to be limited to only the southern portions of the Okanagan
Valley, although it was only first discovered in Canada in 1980. It may also be found
farther north in the Okanagan in similar areas. The Canadian populations may be
connected with populations in Washington state. The majority of the range is in
the southwestern US and south into Mexico and central America.
The Nightsnake is mainly limited to hot, dry areas, with near desert conditions. It
is found in both rocky and sandy areas. The Nightsnake is frequently found under
rocks or boards.
Breeding appears to occur in the spring. Females lay 4-6 eggs in late spring to
early summer. The eggs hatch in approximately two months. Hatchlings vary greatly
in size apparently ranging from 13-19 cm in total length.
Nightsnakes are mainly nocturnal and therefore rarely encountered. Most of the day
is spent under cover. The Nightsnake has enlarged grooved teeth at the back of the
upper jaw for holding prey such as frogs. The snake's saliva is mildly toxic and
immobilizes the prey. Nightsnakes will even consume juvenile Western Rattlesnakes.
The Nightsnake is limited to only a small area in southern BC. Virtually nothing
is known about the ecology of the species this far north. To date only a few Night
Snakes have even been seen in BC. The Nightsnake has been designated Endangered by