For the second time in a year biologists at Great Smoky Mountains National Park killed a bear they wrongly thought had attacked a sleeping hiker.

The park had established protocols following last June's incident to avoid another misidentification, including contracting with a lab for quick DNA analysis and use of GPS collars to track the movements of bears suspected in attacks while their DNA was being processed. But in this case the 400-pound bear's neck was too thick to keep the collar in place, and the decision was made to kill the animal, park spokeswoman Dana Soehn said Monday.

“What we have did not work, and they tried for over an hour to where it would not come off," the spokeswoman said during a phone call. "They described it to me as trying to slip it on a cone, because it (the bear's neck) was so much larger than his head.

"... We have put collars on bears this size, it was just this particular bear," added Ms. Soehn. "That doesn’t mean every 400-pound bear is going to be like that, but this one certainly was.”

The bear was captured on May 13, three days after 49-year-old Bradley Veeder, of Las Vegas, Nevada, was bitten on the leg while sleeping in his tent near the Spence Field backcountry shelter. 

The hiker did not have any food in his tent; he had hung his supplies from the bear cables provided at backcountry sites in the park, park officials said at the time. After the incident, all backcountry campers gathered in the shelter for the rest of the night.

"The bear did return later to the area where it tore through Veeder’s vacant tent, along with another vacant tent. The bear was not seen by any of the backpackers in the area," a park release said at the time.

Last June a teenager was attacked by a bear while sleeping in a hammock elsewhere in the park's backcountry. The boy's father, who was sleeping nearby, also in a hammock, was able to scare off the bear and get his son medical treatment. Three days later park staff captured a bear near the campsite, put it down, and obtained DNA samples to compare to DNA recovered from the attack site.

Analysis of those samples, completed almost two weeks after the bear attack, determined that the wrong bear had been killed. The one that attacked the teen never was found, although rangers searching the area around the site on June 7 fired shots at a bear that ran off into the woods.

After that episode, Great Smoky officials announced that they were working with a forensics lab to develop a DNA analysis procedure that could prevent similar misidentifications in the future. They still, however, need to perfect the process for confining suspect bears while the testing is being conducted.

While they hoped the answer would be GPS collars, this month's incident demonstrated the problems that can arise. While one bear found near the site in the early morning hours of May 20, a 200-pound boar, was fitted with one of the tracking collars, the 400-pound bear captured with help of a tranquilizer dart near sundown on May 13 was simply too big around the neck to wear one, according to park officials. 

"Park wildlife biologists recommended euthanasia of the bear based on a combination of factors including the presence of dental injuries consistent with the hiker’s bite wound, the size and gender of the bear, and being the first and only bear present near the scene of the attack," a park release sent out Monday said. "The large, dominant male bear fit the profile of a bear expected to have been responsible for the attack. The serious incident included not only an aggressive bite through a tent, but also repeated attempts to enter the victim’s tent."

Had the bear been captured near a road, rangers might have been able to bring a culvert trap to place the boar in to await the DNA tests. But Spence Field is far from roads, and physically hauling the bear six miles out of the backcountry by a ground crew so it could be placed in a holding facility pending the outcome of the DNA analysis "was not considered a practical option," the release said.

"If we had a culvert trap, we would have had a different set of options," said Ms. Soehn. "This (location) was hike-in only.”

As for the smaller bear, DNA analysis proved it was not involved in the attack on the hiker, according to park staff.

“Bears are iconic symbols in the Smokies and a decision to euthanize an animal is not made lightly,” said Superintendent Cassius Cash in the release. “Park staff have worked diligently over the last year to develop viable alternatives to euthanasia. Understandably, these options won’t be appropriate responses for every bear incident. In the interest of responsibly protecting hiker safety in America’s most visited national park, we make our decisions based on the best available information for each particular situation.”

There are an estimated 1,600 black bears in the national park, Ms. Soehn said. They typically range in size from a little more than 100 pounds for females to roughly 250 pounds for males, she added.

While the Spence Field shelter currently remains closed to overnight use, no trails in the park have been closed due to bear activity, and the shelter could be open soon, the spokeswoman said.

“They’ll continue monitoring the site, and at some point, just like all sites that we close due to bear activity, we’ll make a decision that we’ve done everything we can to make sure it's reasonably safe and reopen it," said Ms. Soehn.

Bears have been somewhat of a problem across the park this spring, according to the spokeswoman. 

“We have reports of bear aggressive behavior from multiple sites across the park. May and June is typically a tough time for bears" because of a lack of natural forage, she said.

While no other visitors have been attacked this year, Ms. Soehn said bears have been "ripping through tents," and that in one incident "we had a bear that was on top of one of our shelters.”