The Harris antelope squirrel has also been called Harris's spermophile, marmot squirrel, grey-tailed antelope squirrel, and Yuma antelope ground squirrel. Ammospermophilus is derived from ammos (sand), spermatos (seed), and philos (loving or desiring affinity). The term harrisii honors Edward Harris.
Ammospermophilus harrisii is the most conspicuous small diurnal mammal of the desert plains from Tucson to the Colorado River.
(Best et al. 1990)
Perception Channels: tactile ; chemical
In some parts of its range, the Harris antelope squirrel is losing habitat to agriculture and other human developments. It is considered threatened in the state of California. (Nowak 1991)
IUCN Red List of Threatened Species: least concern
Harris antelope squirrels can be a nuisance in irrigated areas because they raid crops and burrow through ditch banks. Some ground squirrels are suspected to be reservoirs of bubonic plague. (Nowak 1991)
The Harris antelope squirrel is omnivorous. It feeds on seeds, fruit, plant stems and roots, some insects, and carrion. It has cheek pouches of considerable capacity. Suitable food supplies are carried in the cheek pouches and stored in burrows, under rocks, or in some other shelter. (Nowak 1991)
Harris antelope squirrels are found below 1,350m elevation in southwestern United States and northwestern Mexico. (Best et al. 1990)
The Harris antelope squirrel inhabits arid, sparsely vegetated plains and lower mountain slopes. It prefers rocky hills or rocky soils. (Nowak 1991)
Terrestrial Biomes: desert or dune
Average lifespan
Status: captivity: 10.6 years.
Head and body length is 137-168mm and tail length is 55-95mm. There are no differences in external measurements between the sexes. Harris antelope squirrels have long necks and slender bodies. The tail is short and the ears are small. The body hair is mouse gray in the winter and paler during the summer. Dorsal hairs are short and somewhat coarse, but lay smoothly, giving the animal a glossy appearance. Hairs on the undersurface are coarse and rigid. Winter pelage is longer and softer than summer pelage. There is one white stripe along both sides of the body from shoulder to rump. The undersurface of the tail is mixed black and white. A white ring encircles each eye, giving the Harris antelope squirrel a spectacled appearance. The soles of the feet are heavily haired. The Harris antelope squirrel carries its tail arched over its back. (Best et al. 1990), (Nowak 1991)
Other Physical Features: endothermic ; bilateral symmetry
Average mass: 126 g.
Although mating can take place from December or January until June, peak reproductive activity occurs from February-March. A vaginal plug is formed after copulation. In females, the beginning of the breeding season is marked by a swelling of the labia, enlargement of the uterus, and opening of the vaginal orifice. In males, spermatogenesis may begin as early as November and lasts until June. The testes regress in size in June and July to less than 10% of the February and March mass. Gestation lasts for about 30 days, and the litter size may range from 5-14. The average litter size is 6.5. Females give birth to only one litter per year. Newborns are naked and the skin is pink and somewhat transparent. The young cannot crawl, and their eyes and ears are closed. After 1 week, the dorsal sides of the head and back are covered with black pigmentation. At 2 weeks, 2 pale stripes appear on the back. These stripes are covered with white hairs in the adult. At 3 weeks, the claws are well-developed and the lower incisors have erupted. At this age, the young still cannot walk without falling over. Between 3 and 4 weeks, the ears open and the young are fully covered with hair. The upper incisors begin to erupt after 4 weeks. At this age, the young are very vocal and frequently utter a trilling noise when disturbed. When trilling, the young generally stand upright and shake all over. Eyes open 29 to 34 days after birth. Running and other movements improve a great deal after the eyes have opened. The young are weaned 7 weeks after birth. The young first emerge from their burrows between 4 and 5 weeks of age. Adult size is attained approximately 217 days after birth. Males reach sexual maturity during their first year. Females are sexually mature at about 10-11 months of age. The vagina does not open until the female is in heat. (Neal 1965), (Best et al. 1990)
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual
Average birth mass: 3.8 g.
Average gestation period: 30 days.
Average number of offspring: 6.8.
Average age at sexual or reproductive maturity (female)
Sex: female: 319 days.
