Wolves and grizzly bears are mostly to blame for a steep population decline in a signature elk herd in the northern range of Yellowstone National Park, government scientists said on Wednesday.

The elk population in the northern section of the park is prized by sportsmen who hunt outside Yellowstone boundaries in Montana and by the millions who pour into the park each year to see wildlife.

Annual counts of the northern Yellowstone elk population show it has plummeted by more than 70 percent since 1995, falling from 16,791 to fewer than 5,000 today.