Family: Sciuridae, Squirrels view all from this family
Description A large prairie dog. Pinkish brown above; whitish or buffy white below. Slim, sparsely haired tail with black tip unique among prairie dogs. Short, rounded ears; large black eyes. L 14–16 3/8" (355–415 mm); T 2 7/8–4 1/2" (72–115 mm); HF 2–2 1/2" (50–65 mm); Wt 32–48 oz (900–1,360 g).
Similar Species No other prairie dog has black-tipped tail.
Breeding Mates February–March. 1 litter per year of usually 4 or 5 young born after gestation of about 30 days.
Habitat Shortgrass prairies.
Range Eastern Montana and sw North Dakota south to extreme se Arizona, New Mexico, and nw Texas.
Discussion During the hot summers in most of its range, the usually diurnal Black-tailed Prairie Dog is most active aboveground mornings and evenings, often sleeping in its burrow to escape midday heat. In cool, overcast weather it may be active all day, but it retreats to its burrow to wait out storms. While it does not hibernate, during periods of severe cold or snowstorms this species undergoes a mild torpor and keeps to its burrow for a few days. About 98 percent of the Black-tailed Prairie Dog’s diet consists of green plants, including various kinds of grasses, such as grama grass, bluegrass, bromegrass, and, in Texas, burro grass and purple needlegrass. It occasionally eats a few insects, especially grasshoppers, and may rarely eat meat. It habitually consumes all the green vegetation around its burrow, not only because it is convenient, but also to clear away protective cover that might shield predators. In the fall, prairie dogs put on a layer of fat that helps them through winter months when food is scarce.
Among the most gregarious of mammals, the Black-tailed Prairie Dog lives in "towns," which may contain as many as several thousand individuals, covering 100 acres (40 ha) or more. The town is divided into territorial neighborhoods, or "wards," which in turn are composed of several "coteries," or family groups of one male, one to four females, and their young of up to two years of age. Sociable animals, Black-tailed Prairie Dogs approach each other, touch noses, and turn their heads sideways to touch incisors; this "kissing" is not a part of courtship but a gesture of recognition and identification among ward members. The animals also groom one another and cooperate in the building of burrows. The burrows have conical entrance and exit mounds, which prevent flooding and serve as vantage points at which prairie dogs often sit on their haunches to survey their surroundings and scan for danger. The mounds are of different heights to facilitate airflow through the burrow. About 3 to 5 feet (1–1.5 m) below the entrance a short, lateral tunnel serves as a listening post and turn-around point, and at the bottom of the entrance shaft, which is up to 14 feet (4 m) deep, a long, horizontal tunnel features several nesting chambers lined with dry grass, and an excrement chamber. A prairie dog covers its scat with dirt, and as one excrement chamber is filled up, a new one is excavated. The Black-tailed rarely wanders far from the safety of its burrow. Prairie dogs mate in late winter or early spring. The young, born deaf, blind, and hairless, don’t emerge from the burrow until six weeks of age. They begin fending for themselves at about 10 weeks, and are fully grown at six months.
Like many gregarious mammals, the Black-tailed Prairie Dog is highly vocal. Studies with a sound spectrogram indicate that it has nine distinctive calls, including chirps and chatters much like those of a tree squirrel; snarls, used when fighting; squeals of fright; and a shrill bark that gives this animal its common and genus names (Cynomys comes from Greek words meaning "dog mouse"). A staccato, double-noted call consisting of a chirp followed by a wheezing sound and accompanied by tail flicking is an alarm signal; it is chorused by other prairie dogs before all dive for safety. The "jump-yip" display, in which the prairie dog leaps into the air with head thrown back and forelegs raised as it gives a wheezing, whistling yip, seems to be an all-clear signal; this is also picked up by other prairie dogs, and soon the whole community is jumping and yipping.
The average life span of the Black-tailed is seven to eight years. In the past, prairie dog towns covered vast expanses of the Great Plains. After great numbers of American Bison were killed off, the use of the prairie for agriculture and grazing allowed a prairie dog population explosion. However, as the rodents competed with cattle for grass—-250 prairie dogs can consume as much grass each day as a 1,000-pound (450 kg) cow—they became the object of such fierce extermination campaigns that their numbers declined by more than 90 percent (which, in turn, led to the decline in numbers of their chief predator, the Black-footed Ferret). Now foxes and the American Badger are this prairie dog’s chief predators, but Coyotes, Bobcats, eagles, hawks, and snakes also take a share. In some areas, ranchers still attempt to eliminate prairie dogs with cyanide. However, a balanced population of the animals (controlled by predators, sport hunters, and modern methods of habitat modification) can actually improve rangeland, and today many ranchers take pains to maintain dog towns instead of eliminating them. Prairie dog meat once provided food for Native Americans and early settlers.
