The Prairie Dog: Friend Or Foe? Farmers and ranchers hate them. Scientists learn from them. Families enjoy watching them. Whatever their viewpoint, most people living on the prairie have a strongly-held opinion on prairie dogs. Prairie dogs are members of the rodent family, the largest group of mammals in the world. They live in colonies on the prairie that range in size from one acre to several thousand acres. The number of prairie dogs in North America in 1920 was about 5 billion, according to naturalist Ernest Thompson Seton, and the subterranean towns they created covered more than 2 million acres. But years of purposeful eradicati