An unidentified Yellowstone National Park hiker was mauled by a grizzly bear while hiking with his wife.

The man's identity and hometown have been withheld to allow police to notify family members. He and his wife were hiking the Wapiti Lake trail and aout a mile-and-a-half from its start, he was attacked. Nearby hikers heard his wife plea for help and called park rangers immediately.

The husband and wife couple had traveled about a mile and a half in on the trail Wednesday morning when they surprised a grizzly sow with cubs. In an apparent attempt to defend a perceived threat to her cubs, the bear attacked and fatally wounded the man, the National Park Service said in a statement.

The bears have yet to have been captured. Park authorities have not said what they plan to do with the bear if she is captured. They have closed off the areas near the attack for the time being.

It is extremely unfortunate that this couple's trip into the Yellowstone backcountry has ended in tragedy, said Dan Wenk, Superintendent of Yellowstone National Park. Our heart goes out to the family and friends of the victim as they work to cope with their loss.

A spokesperson for Yellowstone told Reuters if there is an aggressive bear that continually poses a threat to human safety, it will be removed.

The fatal bear attack is the first at Yellowstone since 1986. The famous park is home to approximately 600 grizzly bears. However, Diane Shober, an employee of the state Wyoming Travel and Tourism agency, said the likelihood of another attack is small.

Park visitors are encouraged by the rangers to stay on designated trails, hike in groups of three or more people, and to be alert for bears and make noise in blind spots. They also advise hikers to carry bear pepper spray, which is an effective tool in thwarting off bears.