The survival of pups is quite high, since they remain underground until 6 weeks of age. However, mortality during the first year is about 50 percent. Prairie dogs are very social animals, living in towns which generally range in size from 1 to 1,000 acres. Naturalist Earnest Thompson Seton estimated that about 5 billion prairie dogs inhabited North America in the early 1900s. The coterie usually consists of an adult male, several adult females, and any offspring under 2 years old.
Coterie members maintain unity through physical contact such as elaborate grooming.
One of the most obvious features of a prairie dog town is the abundance of mounds and holes which lead to a complex system of underground tunnels. With soil excavated from these tunnels, prairie dogs construct dome-shaped mounds to use as lookout posts and to prevent water from entering their burrows. Prairie dogs lead active lives, spending most of their time aboveground foraging. Grasses make up most of their diet, along with forbs and occasionally seeds and insects. When prairie dogs are above ground, they constantly communicate with members of their coteries and adjoining neighborhoods.