A mother grizzly previously allowed to roam free after killing a hiker in Yellowstone National Park in July has been euthanized after being linked to a second fatal bear mauling in August, park officials said on Monday.
DNA and footprint analysis showed the bear from July's attack was among as many as seven grizzlies associated with the second victim, John Wallace, whose remains were found within 24 hours of his death, Park Superintendent Dan Wenk said.
Wallace, 59, from Chassell, Michigan, had been hiking alone through the backcountry along the Mary Mountain Trail when he died. His body was discovered by two other hikers on August 26.
We will more than likely never know what role, if any, the sow might have played in Mr. Wallace's death, Wenk said in a statement.
But because DNA analysis indicates the same bear was present at the scene of both fatalities, we euthanized her to eliminate the risk of future interaction with Yellowstone visitors and staff, he added.
The two bear maulings in July and August marked the first fatal grizzly attacks on humans in Yellowstone since 1986.
The 250-pound female euthanized on Sunday was previously identified as the grizzly that attacked and killed Brian Matayoshi, 58, who inadvertently surprised the bear and its two cubs as he and his wife were hiking along the Wapiti Lake Trail on July 6.
Investigators concluded the California couple may have unwittingly helped provoke the attack by running from the animal in panic, heightening the bear's chase response.
Because the mother grizzly was believed to have acted in a purely defensive manner to protect its young and had no known previous contacts with humans, park officials initially decided to allow it to roam free.
CAME UNDER SUSPICION
But the bear came under suspicion a month later when Wallace turned up dead within miles of July's mauling, and officials said then that they would compare DNA samples from the two incidents to learn whether the mother grizzly was involved in both. Those tests came back positive.
Park officials had been keeping tabs on the mother grizzly via reconnaissance flights since July, park spokesman Al Nash said, adding that a patch of white fur visible on one of the cubs made their movements easy to track. The sow, aged 6 or 7 years, was captured in a live trap on September 28.
The two cubs, trapped the next day, were sent to a public refuge for orphaned and injured wildlife called the Grizzly and Wolf Discovery Center in West Yellowstone, Wenk said.
In their probe of Wallace's death, investigators determined that at least nine grizzlies were feeding on two nearby bison carcasses, one just 150 yards from him. Seventeen bear rest spots, or daybeds, also were found in the vicinity.
Yellowstone rangers will continue efforts to trap other bears definitively linked to the Wallace mauling, and the fate of any they capture will be decided on a case-by-case basis, Nash said.
Earlier in August, park officials euthanized a 4-year-old male grizzly after that animal charged a man sitting on a trail near Yellowstone Lake. That hiker was unhurt, but the bear was determined to pose a hazard to park visitors because of previous encounters.
Yellowstone averages just one bear-related human injury for every 3 million visitors, or about one a year, though no visitors were hurt by bears in all of 2010.