Black-tailed Prairie Dog

Cynomys ludovicianus (Ord)

 Color photo by David M. Watson.
Copyright 1999.   All rights reserved.

Description:   The black-tailed prairie dog is a heavy-bodied, short-legged rodent closely related to other ground squirrels. It can be distinguished from other Kansas members of the squirrel family by: 1) coarse, pinkish cinnamon hair, grizzled with buff and black on the upperparts, 2) relatively short, flat tail tipped with black hairs, 3) underside of tail lighter than dorsal side, 4) broad head with large eyes which contrast with the short round ears, and 5) buffy-white underparts. In winter the hair is longer than in summer. Young can be distinguished from adults by the ochraceous-cinnamon color of their upperparts and fewer white and black hairs. Sexes are similar in color, and females are 10 to 15% smaller than males. Young are nearly adult size by the end of summer.

Size:   Adults may attain the following dimensions; total length 355-415 mm; tail 54-99 mm; hind foot 50-67 mm; ear 8-14 mm; weight 406-1390 grams.

Range and Habitat:   Black-tailed prairie dogs inhabit the western half of the state, in short-grass prairie or areas of hard soils and low-growing vegetation. Colonies have become rare in many places as a result of human persecution.

Reproduction:   Black-tailed prairie dog mate underground in late February or early January, and after a gestation period of 33 to 38 days a single litter of one to eight young (usually three or four) are born, hairless and with closed eyes. Yearlings seldom reproduce and two-year-old females produce fewer young than older females. In thirteen days the young are covered with fine hair and by 26 days they are well furred. The young are particularly vulnerable at this time, and many litters are killed by other mothers. Such infanticide may serve to reduce competition, or otherwise improve the chances of the killer's own pups surviving. In 33 to 37 days the eyes open and the pups can call. In six weeks they come above ground and forage on green vegetation, but are not completely weaned until a few days later. During this time they often nurse from any lactating female. By October, the young have reached 60 to 65% of adult size.

Habits:
   Prairie dogs are highly social animals, and live in large colonies which may contain hundreds or even thousands of individuals. An area inhabited by prairie dogs is recognized by the presence of numerous mounds of soil surrounded by bare ground or closely cut vegetation. Close examination will reveal individual prairie dogs sitting upright on or near the edge of the burrows, while others feed nearby. If one approaches a colony, alarm calls are given and there is considerable movement as the animals run to their burrows. They may remain at the edge of the burrow, calling and flipping their tails, but if approached too closely, will retreat into their dens. To ensure good visibility, the areas in and around the colony are clipped nearly bare of vegetation, permitting easy detection of predators.

 Female near burrow: Wichita Mts., OK. Color photo by George R. Pisani.
Copyright 1999.   All rights reserved.

The burrow system of black-tailed prairie dogs is unique, especially the surface entrance. Here the soil excavated from below is packed into a substantial dike around the funnel-shaped entrance. These rims of soil provide a vantage point from which to observe approaching predators. They also form a barrier in case the colony is inundated by a flash flood. If water enters the holes, air pockets in the tunnels permit survival until the flood waters subside. The subterranean tunnels are extensive, and after descending one to three meters nearly perpendicular to the surface, they angle horizontally for another three to five meters. Several blind side tunnels are excavated lateral to the main tunnel and at the end of one of them is a nest chamber lined with dry grasses and other vegetation. During the night and in the hotter part of the day black-tailed prairie dogs spend their time resting in these subterranean tunnels and chambers. Except during the breeding season, several prairie dogs will often share one burrow. During periods of bad winter weather they remain below ground almost continuously. Fat is accumulated for this period of inactivity, but black-tailed prairie dog do not hibernate, and may be active in periods of good weather throughout the winter. The same burrows are used for generations and are passed down to female relatives. Because of this stability in burrows, neither the number nor density of holes is an accurate measure of the prairie dog population.

Food:   The food of the black-tailed prairie dog consists of native grasses and other plant material as well as occasional animal material, especially insects. It will feed on those kinds of foods that are available.

Remarks:   Maximum longevity is approximately eight years. Black-tailed prairie dogs are vulnerable both above-and below-ground. Eagles and large hawks dive on inattentive animals while black-footed ferrets, snakes, and badgers attack within the burrow system. Foxes, bobcats, and coyotes also feed upon prairie dogs.

The greatest threat to prairie dogs in Kansas is human persecution. Prairie dogs are believed to compete with livestock and are extensively poisoned on rangeland. However, prairie dogs provide a number of important services for the prairie community and their towns are actually preferred by other herbivores. For example, bison and pronghorn prefer to graze in prairie dog towns, where the activities of the prairie dogs increases nutrient cycling. Bison grazing in prairie dog towns forage more efficiently and put on more weight than when they forage elsewhere. Prairie dog towns also provide homes for black footed ferrets and burrowing owls, and foraging areas for insect eating birds such as the mountain plover.


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