© AP Photo/Yellowstone National Park, James PeacoIn this 2005 file photo, a grizzly bear moves through the brush at Yellowstone.

It's the first such fatality in 25 years

A man out on a hike with his wife in Yellowstone National Park's backcountry was killed by a female grizzly after the couple apparently surprised the bear and its cubs today, park officials said. The attack was the first fatal bear mauling in the park since 1986. "In an apparent attempt to defend a perceived threat to her cubs, the bear attacked and fatally wounded the man," said a park statement. "Another group of hikers nearby heard the victim's wife crying out for help, and used a cell phone to call 911."

Investigators have been interviewing the woman about the attack, which took place on the Wapiti Lake Trail, close to Canyon Village and near the middle of Yellowstone. Park officials haven't taken any action against the bear. Yellowstone and surrounding areas are home to a growing number of grizzlies, at least 600 and some say more than 1,000. Once a rare sight, they've become an almost routine cause of tourists lining up at Yellowstone's roadsides at the height of summer season.