Mount Mckinley, elevation 20,320 feet, is the highest mountain in North America and overshadows the Denali study area. (Photos by Thomas J. Meier)

John Burch and others weigh a radio-collared wolf they are about to release. (Photo by Thomas J. Meier)

The Denali Caribou Herd numbered 2,300 to 3,100 during our study. (Photo by L. David Mech)

Radio collars weighing 1.3 pounds (580 grams) were placed on 147 wolves from 30 packs in and around Denali. (Photo by L. David Mech)