A grizzly bear killed a 57-year-old man hiking in Yellowstone National Park with his wife Wednesday. It's the first fatal bear mauling in the park since 1986.

The bears involved in Wednesday's encounter have not been captured, and park officials said they did not immediately have enough information to determine what measures, if any, they might take in the aftermath of the attack.

According to the AP, Yellowstone National Park is home to at least 600 grizzly bears, though some say the population is over 1,000. While the attack is the first fatal mauling in the park since 1986, it's the third in the region in little over a year.

A National Park Service statement said the couple surprised the mother grizzly while with her cubs, and that the grizzly fatally mauled the man in "an attempt to defend a perceived threat to her cubs."

This news item text sample is arranged from http://www.huffingtonpost.com/2011/07/07/yellowstone-national-park-grizzly-bear-attack_n_892050.html