A mountain goat that fatally gored a hiker, then stood over the man and stared menacingly at people trying to help, had shown aggressive behaviour in the past, Olympic National Park officials in Washington state said Monday.

Robert Boardman, 63, of Port Angeles died Saturday after he was attacked by the goat while hiking on the subalpine Switchback Trail. The trail is popular with residents of nearby Port Angeles, about 140 kilometres west of Seattle.

Park rangers later found the goat, saw blood on it and shot the animal.

Rangers have been tracking the goat and others for the past four years because they have followed people or approached hikers without backing down, said park spokeswoman Barb Maynes.

"It has shown aggressive behaviour, however, nothing led us to believe it was appropriate to take the next level of removal," she said. "This is a highly unusual. There's no record of anything similar in this park.

"It's a tragedy. We are taking it extremely seriously and doing our best to learn as much as we can."

Park officials have posted signs at trailheads warning hikers to be watchful of all goats and to stay at least 30 metres from the animals. Hikers are also warned not to urinate on or near the trail, because goats are attracted to the salt.

A necropsy, or animal autopsy, was conducted on the goat Sunday night by private veterinary pathologists. Park officials are awaiting test results of blood and tissue samples, which may take a couple of weeks, Maynes said.

"We're looking for anything to indicate any presence of diseases, which might shed light on the animal's extremely strange and unusual behaviour," she said.

Hiking with wife

Boardman was hiking with his wife, Susan Chadd, and their friend, Pat Willits, and had stopped for lunch at an overlook when the goat began acting aggressively toward them, the Peninsula Daily News reported.

Boardman urged the others to go ahead while he tried to get rid of the goat, according to the paper. The two heard him yell and ran back to help.

Hikers who came upon the group radioed for help. But it took nearly an hour before rescuers could reach Boardman because the goat stood over him as he lay motionless on the ground, according to the Seattle Times.

"The mountain goat was terribly aggressive," Jessica Baccus, who was hiking with her family, told the Times. "It wouldn't move. It stared us down."

She and her husband, Bill Baccus, a park scientist, tried to lure the goat away by pelting the animal with rocks, shouting at it and using a silver reflective blanket to distract it. It finally moved away, and Jessica Baccus tried to give Boardman cardiopulmonary resuscitation until a local doctor who came upon the group took over, she told the Times.

A U.S. Coast Guard helicopter flew him out of the park.

Boardman, a locally known musician and diabetes educator, was an avid hiker who also worked for years as a nurse for the Makah and Lower Elwha Klallam tribes, according to the Peninsula Daily News.

About 300 goats graze the park's alpine meadows and roam its rocky peaks. The animals are not native to the park and were introduced in the 1920s, before the park was established.

Maynes said the park had a two-year live capture program in the late 1980s to remove the goats by helicopter because of the damage the animals caused to the park's fragile alpine areas and soil.

That program was ended after two years because it was determined to be risky for operators and was ineffective, she said.