The black-tailed prairie dog (Cynomys ludovicianus) is a rodent of the family Sciuridae (the squirrels) found in the Great Plains of North America from about the United States–Canada border to the United States–Mexico border. Unlike some other prairie dogs, these animals do not truly hibernate. The black-tailed prairie dog can be seen above ground in midwinter. A black-tailed prairie dog town in Texas was reported to cover and included 400,000,000 individuals. Prior to habitat destruction, the species may have been the most abundant prairie dog in central North America. It was one of two prairie dogs described by the Lewis and Clark Expedition in the journals and diaries of their expedition.
Description Black-tailed prairie dogs are generally tan in color, with lighter-colored bellies. They may have color variation in their pelt, such as dark fur on their back in black and brown tones. Their tails have black tips, from which their name is derived. Adults can weigh from , males are typically heavier than females. Body length is normally from , with a tail. The black-tailed have black long claws used for digging in the ground. The body of the black-tailed prairie dog is compact, and the ears are quite small and close to the head.
Distribution The historic range of the black-tailed prairie dog was from southern Saskatchewan and Alberta to Chihuahua, Mexico, and included portions of Montana, North Dakota, South Dakota, Wyoming, Colorado, Nebraska, Kansas, Oklahoma, Texas, Arizona, and New Mexico.Hall, E. Raymond; Kelson, Keith R. (1959). The mammals of North America. New York: Ronald Press Company. black-tailed prairie dogs occur across most of their historic range, excluding Arizona;Johnsgard, Paul A. (2005). Prairie dog empire: A saga of the shortgrass prairie. Lincoln, NE: University of Nebraska Press. Mulhern, Daniel W.; Knowles, Craig J. (1997). "Black-tailed prairie dog status and future conservation planning". In: Uresk, Daniel W.; Schenbeck, Greg L.; O'Rourke, James T., tech. coords. Conserving biodiversity on native rangelands: symposium proceedings; 1995 August 17; Fort Robinson State Park, NE. Gen. Tech. Rep. RM-GTR-298. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: pp. 19–29. however, their occupied acreage and populations are well below historic levels.Luce, Robert J. (2006). "A multi-state approach to black-tailed prairie dog conservation and management in the United States". In: Basurto, Xavier; Hadley, Diana, eds. Grasslands ecosystems, endangered species, and sustainable ranching in the Mexico-U.S. borderlands: conference proceedings. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: pp. 48–52.
Habits Black-tailed prairie dogs are diurnal. Above-ground activity is reduced when rain or snow is falling and during days when the temperature exceeds . During the winter months, black-tailed prairie dogs do not fully hibernate. They continue to leave the burrow to forage, but will enter a state of torpor at night to conserve energy. Torpor is categorized by a drop in metabolism, heart rate and respiration similar to hibernation, but is involuntary and shorter in duration. On average, black-tailed prairie dogs will lose twenty percent of their body weight during the fall and winter seasons when they go through bouts of torpor. As winter progresses, the amount of time spent in torpor increases. Between different colonies the overall time spent in torpor varies, independent of prairie dog body mass. This may be due to weather during the previous growing season. As black-tailed prairie dogs receive most of their water from their diet, in years with poor rainfall, the black-tailed prairie dogs spend more time in torpor.
Habitat Black-tailed prairie dogs are native to grassland habitats in North America. They inhabit shortgrass prairie, mixed-grass prairie,Clippinger, Norman W. (1989). Habitat suitability index models: black-tailed prairie dog. Biol. Rep. 82 (10.156). Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. sagebrush steppe, and desert grassland.Long, Dustin; Truett, Joe. (2006). "Ranching and prairie dogs". In: Basurto, Xavier; Hadley, Diana, eds. Grasslands ecosystems, endangered species, and sustainable ranching in the Mexico-U.S. borderlands: conference proceedings. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: pp. 87–89.
Habitat preferences for the black-tailed prairie dog are influenced by vegetative cover type, slope, soil type, and amount of rainfall.Reading, Richard P.; Beissinger, Steven R.; Grensten, John J.; Clark, Tim W. (1989). "Attributes of black-tailed prairie dog colonies in northcentral Montana, with management recommendations for the conservation of biodiversity". In: Clark, Tim W.; Hinckley, Dan; Rich, Terrell, eds. The prairie dog ecosystem: managing for biological diversity. Montana BLM Wildlife Tech. Bull. No. 2. Billings, MT: U.S. Department of the Interior, Bureau of Land Management: pp. 13–27. In cooperation with: Montana Department of Fish, Wildlife, and Parks. Their foraging and burrowing activities influence environmental heterogeneity, hydrology, nutrient cycling, biodiversity, landscape architecture, and plant succession in grassland habitats.King, John A. (1955). "Social behavior, social organization, and population dynamics in a black-tailed prairie dog town in the Black Hills of South Dakota". In: Contributions from the Laboratory of Vertebrate Biology. Vol. 67. Ann Arbor, MI: University of Michigan.
Landscape-scale habitat characteristics
Black-tailed prairie dogs inhabit grasslands, including short- and mixed-grass prairie, sagebrush steppe, and desert grasslands. Shortgrass prairies dominated by buffalo grass (Buchloe dactyloides), blue grama (Bouteloua gracilis), and western wheatgrass (Pascopyron smithii), and mixed-grass prairies that have been grazed by native and non-native herbivores are their preferred habitat. Slopes of 2% to 5% and vegetation heights between are optimal for detecting predators and facilitating communication.
In the Great Plains region, black-tailed prairie dog colonies commonly occur near rivers and creeks. Of 86 colonies located in Mellette County, South Dakota, 30 were located on benches or terraces adjacent to a creek or floodplain, 30 occurred in rolling hills with a slope more than 5°, 20 were in flat areas, and six were in badland areas. The slopes of playa lakes in the Texas Panhandle and surrounding regions are used as habitat for the black-tailed prairie dog.Pruett, Alison L.; Boal, Clint W.; Wallace, Mark C.; Whitlaw, Heather; Ray, Jim. 2004. Playa lakes as habitat reserves for black-tailed prairie dogs. In: Wallace, Mark C.; Britton, Carlton, eds. Research Highlights – 2004: Range, wildlife, and fisheries management. Volume 35. Lubbock, TX: Texas Tech University: 17. Colonies in Phillips County, Montana, were often associated with reservoirs, cattle salting grounds, and other areas affected by humans.
Black-tailed prairie dogs tolerate "high degrees" of disturbance over long periods of time. New colonies are rarely created on rangeland in "good" to "excellent" condition; however, continuously, long-term, heavily grazed land reduces habitat quality due to soil erosion.Rickel, Bryce. (2005). Chapter 3: "Small mammals, reptiles, and amphibians". In: Finch, Deborah M., ed. Assessment of grassland ecosystem conditions in the southwestern United States: wildlife and fish. Vol. 2. Gen. Tech. Rep. RMRS-GTR-135-vol. 2. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 35–69 Black-tailed prairie dogs may colonize heavily grazed sites, but do not necessarily specialize in colonizing overgrazed areas. Overgrazing may occur subsequent to their colonization.Stobodchikoff, C. N.; Robinson, Anthony; Schaack, Clark. (1988). "Habitat use by Gunnison's prairie dogs". In: Szaro, Robert C.; Severson, Kieth E.; Patton, David R., technical coordinators. Management of amphibians, reptiles, and small mammals in North America: Proceedings of the symposium; 1988 July 19–21; Flagstaff, AZ. Gen. Tech. Rep. RM-166. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: pp. 403–408. Black-tailed prairie dogs were associated with areas intensively grazed by livestock and/or areas where topsoil had been disturbed by human activities in sagebrush-grassland habitat on the Charles M. Russell National Wildlife Refuge and Fort Belknap Agency, Montana. Roads and cattle trails were found in 150 of 154 black-tailed prairie dog colonies, and colonies were located significantly closer to livestock water developments and homestead sites than randomly located points.
Soil
Black-tailed prairie dog distribution is not limited by soil type, but by indirect effects of soil texture on moisture and vegetation. Colonies occur in many types of soil, including deep, alluvial soils with medium to fine textures, and occasionally gravel. Soil not prone to collapsing or flooding is preferred. Though they do not select specific types of soil to dig burrows, silty loam clay soils are best for tunnel construction. Surface soil textures in colonies near Fort Collins, Colorado, varied from sandy loam to sandy clay loam in the top 6 in (15 cm), with a sandy clay loam subsoil. In northern latitudes, colonies commonly occur on south aspects due to the dominance of grasses over shrubs and increased solar radiation during winter. Burrows usually occur on slopes more than 10°.Koford, Carl B. (1958). "Prairie dogs, whitefaces, and blue grama". Wildlife Monographs No. 3. Washington, DC: The Wildlife Society.
Black-tailed prairie dogs mix the soil horizons by raising soil from deeper layers to the surface. This may significantly affect the texture and composition of soil at different layers. Their feces, urine, and carcasses also affect soil characteristics.
Home range and population density The home range and territorial boundaries of black-tailed prairie dogs are determined by the area occupied by an individual coterie. Coteries typically occupy about .
Population density and growth are influenced by habitat quality and are restricted by topographic barriers, soil structure, tall vegetation, and social conditions. Urbanization and other types of human development may restrict colony size and spatial distribution. Most plains habitats support at least 13 black-tailed prairie dogs/ha.
Cover requirements
Burrows created by black-tailed prairie dogs serve as refuges from the external environment and are one of the most important features of their colonies. Burrows are used for breeding, rearing young, and hiding from predators, and are maintained from generation to generation, and serve as stabilizers on the physical and social aspects of the colony. Black-tailed prairie dog nests are located underground in burrows and are composed of fine, dried grass. Nest material is collected throughout the year by both sexes and all age classes. Tunnel depths in central Oklahoma were typically deep.Wilcomb, Maxwell Jeffers Jr. (1954). A study of prairie dog burrow systems and the ecology of their arthropod inhabitants in central Oklahoma. Norman, OK: University of Oklahoma. Dissertation. Most colonies contain 20 to 57 burrows/acre.