Autopsy results confirmed that Lance Crosby, 63, died as a result of traumatic injuries sustained from a grizzly bear attack, park officials said. Additional evidence also pointed to the female bear as his attacker, they said.
Two twin female cubs captured with her will be transferred to the Toledo Zoo sometime this fall, the zoo announced Friday. The cubs, which weigh around 50 pounds right now, are less than a year old. Wildlife officials said they're too young to survive in the wild without their mother. An adult female grizzly can weigh up to 500 pounds.
"An important fact in the decision to euthanize the bear was that a significant portion of the (hiker's) body was consumed and cached with the intent to return for further feeding," the park said in a media statement. "Normal defensive attacks by female bears defending their young do not involve consumption of the victim's body."
The grizzly was captured shortly after park rangers found Crosby's body on August 7. A DNA analysis confirmed her hair was found near the body.
The park detailed additional evidence as well: The adult bear and two cubs were at the attack site when park rangers found Crosby's body, a female bear tracks and her cubs' tracks were found near the body, and puncture wounds on the victim were consistent with the captured female grizzly's bite.
"As managers of Yellowstone National Park, we balance the preservation of park resources with public safety," said Yellowstone National Park Superintendent Dan Wenk. "Our decision takes into account the facts of the case, the goals of the bear management program and the long-term viability of the grizzly bear population as a whole, rather than an individual bear."
Crosby was a long-term seasonal employee of Medcor, a company that operates three urgent-care clinics in Yellowstone. An experienced hiker, he had worked and lived in Yellowstone for five seasons, the park said.
He was reported missing Friday morning when he did not report for work. A park ranger found his body in a popular off-trail area less than a mile from Elephant Back Loop Trail, an area he was known to frequent. That trail and other areas, which had been closed after the attack, will reopen Friday.
This was the first fatal human-bear encounter in Yellowstone in 2015, park spokeswoman Amy Bartlett said.
Deadly encounters between bears and humans are rare in Yellowstone. From 1872 to 2011, black and grizzly bears killed seven people in the park, according to its website
. And from 2007 to 2013, wildlife killed only six people in the entire national park system, according to the National Park Service.
The grizzly bear population in the Greater Yellowstone Ecosystem was estimated to be between 674 and 839 in 2014, according to the National Park Service.
Yellowstone is bear country, and park officials strongly encourage hikers to travel in groups of three or more
, to carry bear spray that is easy to grab and to make noise while hiking to scare away bears. The park requires that people stay at least 100 yards from bears and wolves, and at least 25 yards from other large animals.