Over 50 species of mammals live in the beautiful yet predominately desolate land of Badlands National Park. Among the smallest residents are jackrabbits, cottontails, foxes, badgers and black-tailed prairie dogs. The most cherished are the black-footed ferrets because they were considered extinct in 1980. Today, about 100 of these nocturnal critters live in the Badlands. Another success story is the bison. Once numbering in the millions, they disappeared early in the 20th century. During the 1960s, about 50 were reintroduced from North Dakota. The population now numbers over 300. You may also spot pronghorn antelopes grazing in the plains. If you spook them, you will be amazed how fast they run. Their top speed is 40-50 miles per hour. This herd of Rocky Mountain bighorn sheep were basking in the sunshine.