Distinguishing Features
Canada's only representative of
the Boa family is a small (up to 73 cm) greyish or yellow-brown
snake with a yellow underside. They are generally unmarked or may
have a few dark flecks along the sides. The smooth dorsal scales
and wrinkled skin give it a rubbery appearance. It has a rather
short, blunt tail and narrow ventral (belly) scales (Cook, 1984).
Distribution
Columbia Basin: The distribution
and abundance of this species is not well documented. It will likely
be found in suitable habitat in the southern portion of the Columbia
Basin.
British Columbia: Confined to the
montane forests and woodlands from Quesnel south, most records are
from the Thompson River basin south. Absent from the coast, except
for one record from Vancouver.
Global: From southern British Columbia
south to southern California, central Nevada and southern Utah;
from the Pacific coast, east to north-central Wyoming and western
Montana. The distribution is spotty throughout the range (Cannings
et al.1999).
Habitat
Rubber Boas are found in a variety
of habitats, from mountainous humid regions to the lower, dryer
valleys. They can be found in rotting logs or stumps, or under rocks,
forest litter, bark or in crevices in cliffs (Cannings et al. 1999).
Threats
Habitat degradation caused by forestry
and urban development is thought to be the cause of declines in
southern California. This species is found in a wide variety of
habitats but does require coarse woody debris, therefore may be
affected by logging practices that do not leave any debris. Due
to the Rubber Boa's ability to live in a wide variety of habitats
the listed threats may not be as serious as they may be for species
that have more restricted habitat requirements. Declines anticipated
without a better strategy in place for the long-term supply of coarse
woody debris (Cannings et al. 1999).
Biology
They are nocturnal, thus not commonly observed.
They are carnivorous constrictors, eating mainly small rodents and
shrews, as well as with birds, salamanders and snakes. Rubber Boas
hibernate from about November to March, appearing to be one of our
more cold tolerant snakes (Gregory and Campbell 1984). Body temperatures
have been recorded at less than 7°C, however, pregnant females may
gather together in order to maintain a warm stable body temperature.
Breeding occurs during April and May with 2-8 young born live in
the late summer or fall (Cannings et al.1999).
