Prairie dog and Clark in 1804. Lewis described it in more detail in 1806, calling it the "barking squirrel". On average, these stout-bodied rodents will grow to be between long, including the short tail, and weigh between . Sexual dimorphism in body mass in the prairie dog varies 105 to 136% between the sexes. Among the species, black-tailed prairie dogs tend to be the least sexually dimorphic, and white-tailed prairie dogs tend to be the most sexually dimorphic. Sexual dimorphism peaks during weaning, when the females lose weight and the males start eating more, and is at its lowest when the females
Black-tailed prairie dog prey items. Grasslands inhabited by black-tailed prairie dogs support higher biodiversity than grasslands not occupied by them. Hundreds of species of vertebrates and invertebrates are associated with black-tailed prairie dog colonies. Vertebrate species richness on their colonies increases with colony size and density. West of the Missouri River in Montana, 40% (100 species) of all vertebrate fauna in prairie habitats rely on black-tailed prairie dog colonies for food, nesting, and/or denning. Rare and declining species, such as the black-footed ferret, swift fox ("Vulpes velox"), mountain plover ("Charadrius montanus"), and burrowing owl ("Athene cunicularia") are associated with colonies. Because their foraging