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. They have a complex language which includes warning barks, territorial calls, defense barks, fighting snarls, fear screams, and tooth chattering. These vocalizations aid in uniting all coteries in the town. The warning bark is given at the first sight of danger, and all the prairie dogs react to the signal by repeating the bark and running toward their burrows.