The white-tailed antelope squirrel, Ammospermophilus leucurus, is a very small diurnal species of ground squirrel present in the Mojave Desert and other arid regions of the southwestern United States as well as the Baja California Peninsula of northwestern Mexico.
The underside of its tail is white with one dark band. Subspecies vary from grayish brown to cinnamon. The squirrel’s fur is longer and grayer in winter.
This species of squirrel has an average home range of 14.9 acres, and utilizes approximately 4 acres in its daily activities.
Ammospermophilus leucurus is omnivorous, with foilage amounting to anywhere from ten to sixty percent of its diet, seeds ranging from twenty to fifty percent of its diet and its appetite occasionally extending to arthropods and to a lesser extent vertebrates, mainly lizards and even smaller rodents.
Common in grasslands and marginal pinon-juniper woodlands, white-tailed antelope squirrels are most active during the day.
Easily seen as it darts between bush and under fences, the white tailed antelope squirrel is active throughout the year, unlike other ground squirrels, prairie dogs, and chipmunks. On extremely hot days, these squirrels may overheat slightly and thereupon retire to the cooler temperature of their burrows to cool off. Since these squirrels do not cool evaporatively, they are not water stressed by this behavior.The average body temperature of these squirrels is some one-and-a-half degrees greater than that of humans: 100.13 °F
Nights and other periods of inactivity are spent in underground burrows. Individuals are often solitary.
Of the order Rodentia, the white-tailed antelope squirrel reaches maturity at the age of one year. The maximum longevity of the squirrel observed is 11 years.
Females may give birth to one or two litters of five to fourteen young, called a ‘pups, kits or kittens, during the spring of each year, following a gestation period of 29 days. At birth, the offspring weigh 0.0066 pounds. They will nurse for approximately 66 days. At maturity, adults will range from 7.4 inches to 9.4 inches long or tall to 1.6 inches to 3.4 inches wide, with a typical adult weighing 0.231 pounds, or 3.696 ounces, with some ranging as heavy as five ounces.
The females are called ‘doe’ and males ‘buck’. A white-tailed antelope squirrel group is called a ‘dray or scurry’.
The white-tailed antelope squirrel will store food when it is plentiful.