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Southern Rubber Boa
Charina bottae umbratica
A unique snake found in isolated
locations in the Los Padres National Forest, the southern rubber
boa literally looks and feels like rubber with its smooth, small
scales and wrinkled skin. It also has the unique feature of
having a tail that’s just about the same size as its head, which
it uses to fool its predators. When threatened the snake coils
its body, hides its head within its coils, and elevates its tail
to trick an attacker into attacking the tail – so they often
have scarred tails!
The populations of rubber boas
found in the Los Padres are genetically unique in that
biologists describe them as an “intergrade” between the northern
rubber boa (which ranges from British Columbia and the northern
Rockies to the southern Sierra and central coast) and a southern
subspecies restricted to higher elevations in the San Bernardino
and San Jacinto mountains. These intergrades look like the
southern rubber boa but their genetics more closely resemble the
northern rubber boa.
 Habitat
The southern rubber boa is only
found in California (the green areas marked on the map). On the
Los Padres, the intergrade rubber boa is associated with
forested areas from 6,500 to 8,000 feet in elevation, including
Frazier, Tecuya, and Antimony peaks, Mount Pinos west to Cerro
Noroeste, and Alamo Mountain. It can be found in forests
consisting of Jeffrey pine, black oak, white fir, and other
trees, and most often with very deep soils. Its preferred
habitat is damp woodland and forest, large grassy meadows, and
moist sandy areas along rocky streams. The snake makes extensive
use of rodent burrows, and uses rock outcrops, downed logs, and
a thick pine needle and duff layer for cover.
Unique Characteristics and
Behavior
The rubber boa can vary in color
from olive-green to reddish, tan, or chocolate brown and the
southern rubber boa is the smaller of the subspecies, growing to
no more than about 15 inches in length. It has a “prehensile”
tail adapted to grasp or hold objects, allowing it to easily
climb shrubs and small trees. It is also an excellent swimmer.
The boa preys on small mammals, birds, and lizards, constricting
them before swallowing them whole; however, the snake is very
docile and is considered harmless to humans. It will actually
curl up into a ball when picked up by hand!
The southern rubber boa hibernates
through the winter, and females emerge from hibernation sometime
around April. Mating occurs as soon as the snakes emerge from
hibernation and continues through mid-May. By late August
through September, female boas give birth to 2-8 live young
about seven inches in length in loose soils, often under rocks
or other objects, or inside decaying logs. The snakes are mainly
active in the evening or sometimes on warm, moist, overcast
days. Because of its secrecy and the fact that it lives below
ground most of the time, the southern rubber boa is seldom seen.
Threats
The southern rubber boa is
considered common in its range, but since its range is extremely
limited and is being threatened by development and habitat
degradation, it was listed as a threatened species by the State
of California in 1971. The greatest threats to the southern
rubber boa include habitat loss from resort development,
off-road vehicle use, and logging/wood collecting.
Furthermore, habitat loss for the
southern rubber boa can be caused by the removal of downed logs,
particularly following a wildfire. This threat is of particular
concern in the area burned by the Day Fire in 2006, as the
Forest Service at one point proposed piling and burning downed
trees and authorizing commercial logging in boa habitat. The
removal of vegetation for fuel breaks and forest thinning
projects may also adversely affect southern rubber boas and
their habitat by removing cover and drying out the
soil. ForestWatch is continuing to monitor these projects to
ensure that these unique critters are protected.
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