Top: A ranger photographs a stash of heads in Lamar Valley in Yellowstone. Several poachers have been caught after they took well-known heads to taxidermists that recognized the racks from photographs taken inside Yellowstone. One moronic slob hunter was caught after posing with his illegal trophy with Electric Peak in the background of the photo.

When Congress set Yellowstone's boundaries in 1872, the primary goal was preservation of the geysers and other geothermal wonders. Little thought was given to the migratory habits of its wildlife, about which little was known. The park's higher elevations provide summer range for an estimated 40,000 hoofed grazing animals (ungulates)—elk, bison, pronghorn, deer, bighorn sheep, and moose. Each year the accumulating snow of winter spurs them to lower grassland areas that are warmer and drier, where there is more open range.

Yellowstone’s largest herd of elk winter on the northern range, which covers 540 square miles along the Lamar and Yellowstone river basins, overlapping the boundary between Wyoming and Montana. A third of this area is on public and private lands north of the park.

Earlier this century it was commonly thought that the elk were "overgrazing" the northern range—eating the vegetation more quickly than it could recover and damaging the plant communities, including willow and aspen. To maintain "the right balance" between elk and their habitat, biologists believed the elk numbers had to be periodically reduced. Bison and pronghorn were also blamed for overgrazing. As a result, Yellowstone's grazers were trapped and shipped to other ranges across North America or were shot in the park. When thousands of elk were slaughtered in the 1960s, public outcry led to the 'reductions' ceasing in 1968.

Below: A bull elk stands on one of the hot spring terraces in Mammoth. The green lawns of the old Fort Yellowstone, now the Park Headquarters, are prime territory for the elk each autumn.