Eumeces skiltonianus
(Western Skink)

Key Characteristics

Smooth, cycloid scales

Elongate body

Tail often has a bluish color
(more vivid in juveniles)

Light colored lines on a brown ground color

General Description:
Western Skinks are unique among Idaho lizards in that they are covered with smooth, cycloid scales. These scales give Western Skinks a very glossy appearance. Western Skinks have a somewhat long, slim body and a tail that may be a bright blue color. The tail coloration fades to a gray in adulthood, but usually retains some hint of blue. Western Skinks readily autotomizeClick word for definition (lose) their tails, and the bright blue coloration found on juveniles may add to the wriggling tail's distractability. The rest of the body is also handsomely colored with stripes of tan, cream and brown. There is a wide vertebral stripe (runs down the middle of the back), which is usually a tan color, but on juveniles, it is often a very dark brown. The vertebral stripe is bordered on either side by dark (black or brown) stripes (these are not apparent on juveniles, as their vertebral stripe is the same color). The next stripes are cream or light tan in coloration and extend dorsolaterally (between the back and sides). These light colored stripes are bordered on the sides by a fairly wide dark brown stripe. Finally, there is one more lateral (side) stripe on each side that is a light cream color, this blends into the light ventral coloration. All of the stripes originate on the head and extend onto the base of the tail (Stebbins 1985). Males may have an orange tinge on their chin and sides of their head during breeding season (Nussbaum et al. 1983).

Western Skinks are small to medium-sized lizards that can attain snout-vent length sizes of 76 mm (3 in.) and 201 mm (7.9 in.) total length (Storm and Leonard 1995).

There is relatively little known about the reproduction of Western Skink populations in the Northwest. However, based on information of Western Skinks in Utah, they probably mate in May or June, and deposit 2-6 eggs in July (Nussbaum et al. 1983). Based on the observation of recently hatched neonates in August, we can assume that the eggs hatch sometime during August and perhaps September. One note of interest concerning the reproductive habits of Western Skinks is that the females display parental care for the eggs. The female will stay with the eggs, protecting them against predators, repairing the nest and possibly providing additional heat by baskingClick word for definition and then returning to the nest (Behler and King 1979), (Nussbaum et al. 1983), (Storm and Leonard 1995).

Habitat:
Western Skinks are generally found in a variety of habitats including pinion-juniper forests, grassy areas, desert shrub, talus slopes and canyon rims (Storm and Leonard 1995).  Stebbins (1985) mentions that they are often found in areas associated with water (rocky, brushy areas along streams).  I have encountered Western Skinks at sites that did have water nearby, but as Stebbins states (and based on my own experiences) this isn't a requirement.

Idaho Distribution:
Western Skinks can be found across much of Idaho, with the exception of the southwestern corner, and the southeastern edge of the state.  Ranges from south-central British Columbia to southern Baja California, and east to western Montana, Idaho, eastern Utah, north-central Arizona, and southern Nevada. Also found on some islands off coast of California and Baja California. Isolated populations exist in California and Nevada.

Diet:
Feeds on variety of insects (crickets, beetles, grasshoppers, flies, etc.), spiders, and earthworms.

Ecology:
HibernatesClick word for definition/aestivatesClick word for definition. Inactive in cold, winter weather; duration of inactive period varies with local climate. Secretive; ecology and life history are not well known. In Idaho, night snakes, striped whipsnakes, and raptors are predators.

Reproduction:
In Utah, mating occurs in May or June, female lays 2-6 eggs in July, and eggs hatch in August. Female guards eggs and stays with hatchlings until they disperse from nest.

Conservation:

Status:

Unprotected nongame species

Global Rank:

G5

State Rank:

S5


Species description, key characteristics and original work by John Cossel Jr. © 1997
Species ecological information from Groves et al. ©1997.
Original images provided by Charles R. Peterson, William R. Radke.© 1998
Design and Optimization by Ean Harker©1999, 2000.
DAI layout by Stephen Burton, and Mike Legler © 1999.