General Information: White-tailed Antelope Squirrels (Ammospermophilus leucurus) are the small ground squirrels often seen running around the desert on hot days. They have a dark back with a white stripe on the side, light cheeks, and a white eyering. The legs usually have some reddish, and the belly is white. The underside of the tail is white. Antelope Squirrels often hold their tail up over their back as a sunshade.

The name "white-tailed" refers to the white on the underside of the tail, a characteristic that can be used to separate them from Harris' Antelope Squirrel. White-tails, however, live west of the Colorado River, while Harris' live east of the Colorado River. If you visit Hoover Dam, you can see White-tails begging for food on the Nevada side, and Harris' begging for food on the Arizona side.

Antelope Squirrels are often mistaken for chipmunks, but Antelope Squirrels have white or light on the side of the face, while chipmunks have black and white stripes on the side of the face. Also, Antelope Squirrels live in lower-elevation desert areas (Creosote-Bursage Flats and Mojave Desert Scrub habitat types), while chipmunks live higher in the mountains (Pinyon-Juniper Woodlands to Alpine Tundra habitat types).

White-tailed Antelope Squirrels dig burrows and are responsible for some of the holes under bushes and rocks seen in the desert. Their entrance holes tend to be about 3-inches in diameter, larger in diameter than those of the more common kangaroo rats.

Taxonomy: Order: Rodentia (Gnawing animals); Family: Sciuridae (Squirrels).

Technical Description: Sexes alike. Head and body length to about 6 inches; tail to about 3 inches. Weight to about 5-1/2 oz. Body color reddish-gray. Sides of the body with 2 black stripes separated by one white stripe. Upper surface of tail dark; lower surface white. Usually holds tail over the back, exposing the white underside. Skull with 22 teeth. Females 10 mammae.

Breeding: Breed during spring and early summer. Litters large (5-14). Young leave their underground nest when 6-7 weeks old, but stay with their mother during the first year.

Diet: Vegetation and bugs.

Range: Southwestern Deserts north and west of the Colorado River. Another species (Harris') lives across the river in Arizona. Link to range map.

Comments: Active during the day all year, even during the heat of summer, these squirrels can survive with body temperatures as high as 108 degrees F. They use their white tail as a sunshade, and they often can be seen laying with their belly pushed flat against a shady (cool) patch of ground to cool down.

For More Information:

• On-line Animal Diversity Web.

• Smithsonian National Museum of Natural History.

• The American Society of Mammalogists Species Account (pdf).

Typical feeding position with tail held over the back.

Cooling off by lying stretched out in the shade.

This juvenile squirrel seemed to be out exploring the world for the first time. It sniffed everything and tasted many non-food items.