These lizards are commonly
called "Blue-bellies" or "Swifts."
The Western Fence Lizard measures
3 1/2 to 4 inches (snout-vent length), and is about six
inches in total length.
Coloration ranges from light gray to black with dark
blotches on the back that continue down the tail. Mature male Western Fence
Lizards have bright blue, sometimes greenish, bellies, and the undersides
of their legs are often yellow. Females lack this decorative coloring.
The scales are keeled and somewhat spiny.
There are as many as five subspecies. Only the San Joaquin
Fence Lizard (S. o. biseriatus) and the Channel Islands Fence Lizard
(S. o. becki) occur in our region.
Range and Habitat
The Western Fence Lizard is distributed throughout eastern
Oregon, southwest Idaho, all of Nevada, western Utah, Southern California,
and northwestern Baja California. A disjunct population occurs on Isla
de Cedros; a Pacific Ocean island off of Baja California.
is commonly found from the coast to the highest mountain areas at over
6,000 feet. It isn't found in the desert. This lizard is conspicuous and
common in its range. It thrives in a wide variety of habitats, ranging
from coastal sage scrub and chaparral on the coast and foothills, to the
forests of higher elevations. It's usually found on or near the ground,
in rock and wood piles, tree trunks, and the lower branches of shrubs.
Behavior: This aptly named
lizard enjoys sitting on prominent points, like fence posts, where it can
sun itself, and watch for food and predators. Like many species of lizards,
this one is able to change its general coloration to match its background.
Light colored lizards placed on dark rocks become a darker color. Interestingly,
some lizards remain dark when placed on a light background, mimicking a
shadow cast by an imperfection or crack in the rock surface.
Prey and Predators: Its diet
consists of insects and various other arthropods. Unfortunately,
its love of high places makes it easy prey for snakes, hawks, and predaceous
mammals. Kingsnakes and Striped Racers are particularly fond of fence lizards.
The Western Fence Lizard avoids danger through constant vigilance and fast
Breeding: Mating occurs in
May or June. As many as ten eggs per clutch can be laid as early as July,
producing hatchlings as early as mid-August. Upon hatching, the little
ones measure about 2 1/4 inches in total length.
Did you know...
The bright blue patches along the sides of the body of the
male give this lizard the common name of "Blue-belly."
images - I. Lindsey
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