One of the joys of hiking in Yellowstone is the excitement of finding the world-class rack of a bull elk. There is nowhere else in America where you can find the numbers of large wild animals that you see in the Park. When heads, horns, pieces of petrified wood, or other objects are poached from the Park, the visitor is robbed of the experience of seeing the display of wild abundance that is unique to Yellowstone. More importantly, the calcium in the bones and horns is a vital source of nourishment to a wide variety of critters that make up the web of life in our first National Park.

Over-winter calf mortality, yearling mortality, and adult bull mortality all increase with higher elk population densities. Studies show that summer predation by grizzly bears, coyotes, black bears, and golden eagles takes an average of 32% of the northern range elk calves each year. Mountain lions prey upon elk, as do hunters north of the park (taking about 10% of the northern herd annually through the 1980s).

Gray wolves, eliminated from the park by the 1930s, are being restored, but not because park managers think the wolves will "control" the number of elk. Instead, 15 North American wolf experts predicted that 100 wolves in Yellowstone would reduce the elk by less than 20%, 10 years after reintroduction. Computer modeling of population dynamics on the northern winter range predicts that 75 wolves would kill 1,000 elk per winter, but that elk would be able to maintain their populations under this level of predation, and with only a slight decrease in hunter harvest. Since the restoration of wolves to Yellowstone began in January 1995, scientists have begun to document the effects of wolves on elk and other species. Wolves are preying predominantly on elk, as expected. They have also occasionally preyed upon moose, bison, deer, and even one pronghorn antelope.

The carrying capacity of the northern winter range increased in the 1980s because elk colonized new winter range in and north of the park, wet summers resulted in better plant production, winters were mild, and the fires of 1988 opened forests allowing more ground cover to grow. Since 1985, more than 11,000 acres of elk winter range have been purchased by the State of Montana and the U.S. Forest Service north of the park, increasing elk carrying capacity and reducing conflicts between native wildlife and agriculture.