Grizzly bear numbers down in Yellowstone ecosystem

Grizzly numbers in and around Yellowstone National Park dropped slightly this year, indicating the region's bear population could be leveling off after decades of steady growth, researchers reported this week.

An estimated 593 bears are roaming the region of Wyoming, Montana and Idaho, said Mark Haroldson, a bear researcher with the U.S. Geological Survey. That's down from 602 last year. Since the mid-1980s, the region's bear population had grown at an average rate of 4 percent annually, Haroldson said.

Grizzlies now occupy 19,000 square miles in the three-state region and are pushing into areas where they haven't been seen since the species was driven to near-extinction in the early 20th century, biologists say. Conflicts between bears and humans hit record levels last year, and two hikers were killed by grizzlies this summer in Yellowstone National Park.