The grizzly bear had no history of interfering with park visitors A fatal grizzly bear attack in July at Yellowstone National Park may have been provoked when the victim and his wife fled and screamed, officials say.
In recorded emergency calls, hikers said they heard a woman screaming and a man making animal noises, possibly to scare away the animal.
The bear killed Brian Matayoshi, 57, before picking up his wife Marilyn by her backpack, but she was not harmed.
The animal remains free as its reaction was normal for a surprise encounter.
Park authorities had previously thought the couple reacted correctly when they encountered the mother bear with her cubs on the Wapiti Lake Trailhead, a popular Yellowstone route.
But after an investigation, bear researchers and wildlife agents say the pair's running and screaming helped spur the bear into "a sustained pursuit of them as they fled".
Park officials advise hikers to carry pressurised pepper spray with them for self-defence from bears, but the couple were not carrying any.
There have been two other fatal grizzly attacks in 2011. A hunter was killed by a wounded bear near the Idaho-Montana border last Friday, while a Michigan man died in Yellowstone in August.
In recorded emergency calls, hikers said they heard a woman screaming and a man making animal noises, possibly to scare away the animal.
The bear killed Brian Matayoshi, 57, before picking up his wife Marilyn by her backpack, but she was not harmed.
The animal remains free as its reaction was normal for a surprise encounter.
Park authorities had previously thought the couple reacted correctly when they encountered the mother bear with her cubs on the Wapiti Lake Trailhead, a popular Yellowstone route.
But after an investigation, bear researchers and wildlife agents say the pair's running and screaming helped spur the bear into "a sustained pursuit of them as they fled".
Park officials advise hikers to carry pressurised pepper spray with them for self-defence from bears, but the couple were not carrying any.
There have been two other fatal grizzly attacks in 2011. A hunter was killed by a wounded bear near the Idaho-Montana border last Friday, while a Michigan man died in Yellowstone in August.
