Black-tailed prairie dog

The first thing you notice about a prairie dog town is not the prairie dogs. It is the grass. Inside the town the grass is chewed down to stubble, with cone-shaped mounds of bare dug-up dirt scattered every few yards. Outside the town it stands tall. The line between the two is sharp enough to see from a car window, and on the South Unit Scenic Loop Drive at Theodore Roosevelt National Park the road runs straight through three large towns, so you cross that line six times without getting out.

That mowed grass is the reason other animals show up. When prairie dogs graze a town short, they take the pressure off the broad-leaved plants called forbs, which grass would otherwise crowd out. Forbs are better food, so bison and pronghorn walk into the town to eat them. A prairie dog town looks like a colony of small rodents and works like a salad bar for animals a thousand times their size. Badgers, coyotes, foxes, bobcats, snakes, and hawks come for a different reason, which is the prairie dogs themselves.

Underneath, the town is organized into families called coteries: one adult male, several adult females, and their young under two years old, sharing a network of tunnels with several entrances so there is always another way out. Coterie members recognize each other by touching faces, something close enough to a kiss that it is hard to call it anything else. A litter runs from one to six pups, born in spring and kept underground for about six weeks before they surface.

Then there is the barking, which is where the name came from. It is not a dog sound. It is a series of short, high squeaks, and it moves: one animal picks it up, then the next mound, then the one after that, until the whole town is calling and standing upright and watching you. Researchers who study these calls think they carry more than alarm, that different call patterns go with different kinds of threat. Sit in the car long enough and the calls stop, one mound at a time, and the town goes back to eating.

One thing the calls will not warn you about. Prairie dogs can carry fleas that spread sylvatic plague, and an outbreak can empty a town. Watch from the road. Do not feed them, do not touch them, do not put a hand near a burrow, and give any sick or dead animal a wide berth, because its fleas are already looking for the next warm thing to ride.