Brothers John and Frank Craighead knew there was a problem when they saw fewer and fewer grizzly bears at Yellowstone National Park. But how did grizzlies-with a population size once as big as 100,000-wind up on the endangered species list?.
Describes the thirteen-year-study of grizzly bears done by John and Frank Craighead in Yellowstone National Park, in which their use of the radio-tracking collar and other innovations added to the scope of human knowledge about the grizzly.
