Charina bottae
(Rubber Boa)

Key Characteristics

Smooth scales
Small eyes with vertical pupils
Blunt tail
Small spurs near cloaca
(difficult to see on females)
Small chin shield scales

General Description:
Rubber Boas are generally one solid color dorsally, (dark-brown, tan or olive-brown), and a lighter contrasting color ventrally (yellow or cream).  Rubber Boa scales are small and smooth, and the skin is somewhat loose (this causes these snakes to appear and feel rubbery) (Koch and Peterson 1995).  The head gradually tapers to the body and the tail also gradually tapers, ending in a blunt stub.  This gives these snakes the appearance of having two heads.  In fact, when threatened, Rubber Boas will hide their head in their coils and stick their tail in the air to direct attention from the head, occasionally even striking with their tail.  To add to the disguise, Rubber Boas have small eyes that are hard to distinguish from a distance.  The eyes have a copper or bronze colored iris and a vertical pupil.  

Rubber Boas are medium-sized snakes (Koch and Peterson 1995), generally reaching sizes of around 600 mm (2 ft.) but can attain sizes of up to 830 mm (33 in.), (Storm and Leonard 1995).  Rubber Boas are slow moving, and seem to lack many of the tactics used by other faster snakes to obscure their speed and position (see the account for the Striped Whipsnake).

Rubber Boas are typical boas in that they are viviparous (give birth to live young).  They mate in April or May and then give birth to 2-8 young between August and November (Storm and Leonard 1995).  Normally, Rubber Boas are secretive and seldom encountered in the open.  However, female Rubber Boas can sometimes be found basking out in the open.  Juvenile Rubber Boas resemble adults morphologically, but they are often lighter in coloration (sometimes almost pinkish) (Koch and Peterson 1995).

Habitat:
Rubber Boas can be found in a variety of habitats, ranging from desert shrub to open pine forest.  Often, there is a water source nearby and rocks, woody debris or leaf litter that these snakes use for cover.

Idaho Distribution:
In Idaho, Rubber Boas can be found in appropriate habitat across the entire state.  From southern British Columbia, south to southern California, central Nevada and southern Utah, and east to north-central Wyoming and western Montana. Distribution is spotty.

Diet:
Eats mostly mice and shrews, but may also prey on lizards, snakes, and small birds.

Ecology:
HibernatesClick word for definition/aestivatesClick word for definition, NocturnalClick word for definition/crepuscularClick word for definition. Active from March to November. Kills prey by constriction. Wards off predators by releasing potent musk from anal glands.

Reproduction:
Female bears 2-8 live young from August to November, depending on range (in Northwest, young are born in September).

Conservation:

Status:

Unprotected nongame species

Global Rank:

G5

State Rank:

S5


Design optimization and revision by Ean Harker ©1999, 2000
Original images provided by Charles R. Peterson and John Cossel Jr. ©1998
Original work by John Cossel Jr. © 1998