Wednesday, Oct. 21 began as a normal fall day at Brooks Camp. Bears were fishing and preparing to den up. A sow and two cubs wandered near Naknek Lake.
Then something strange happened -- something that might have gone unnoticed if the bears hadn't wandered in front of the lens of a popular webcam and if it weren't for the thousands of bear cam fans who are always watching.
"We could see the cub stumbling, and its legs not really working, and then it kind of collapsed," said a viewer named Diana.
Diana, who hails from Maryland, is a three-year veteran bear cam watcher who goes by the online name LovetheCams. She was paying close attention when the spring cub started acting strange. That evening, she says, the comment board was swirling with confusion. "Like, what's happening to this cub, what's going on?" she recalls. "The first day the cub moved a little, but it didn't ever return to its feet."
Diana says she took careful notes, counting each respiration. On Friday, Oct. 23, two days after collapsing in front of the camera, the cub took its last breath.
The cub's death was uncharted territory for Katmai National Park and Preserve officials, said Troy Hamon, the park's chief of resource management; they've rarely -- if ever -- witnessed a bear die of an unknown cause.
"We see bears, especially cubs, being killed by other bears; that's why mother bears are very protective. We also know there are a lot of bears that go missing that we never see again … we've found bears at the bottom of cliffs," said Hamon. "But our understanding of the non-traumatic mortality modes is fairly uncommon."
Katmai wildlife staff decided to have the cub necropsied, so a few technicians boated out and collected the 60-pound carcass. They shipped it to the National Wildlife Health Center in Madison, Wisconsin, where the necropsy will be performed.
The death was, from a biologists' point of view, a rare opportunity to learn about bear mortality -- and it was an opportunity that was about to repeat itself.
A few hours after National Park Service staff left with the body of the cub, bear cam viewers noticed a big dark bear-shaped blob lying next to an overturned boat on a sand spit.
Comparing screen-grabs before and after, the viewers noted that the bear shape hadn't been there earlier. They brought this to rangers' attention, and then continued to watch as the bear lay in the same spot for the next two days.
The unusual duration of the bear's repose caught peoples' attention, says Hamon. "We have bears that lay down and sleep for six hours, or even sleep for a day, but when a bear lays down for two days, it's dead," he said.
Rough weather kept the wildlife staff from returning to the second body for a few days, but Hamon says he and other soon rangers determined that the deceased was an adult male.
"The reason I knew that," said Hamon, "is because there were also video clips of a sow and two cubs walking along, seeing this animal, startling and running."
This was a telling reminder of bear social dynamics.
"The bear hierarchy system is very funny," Hamon explained. "A very important bear remains very important even after death."
Meanwhile on the comment board, people now had two bears to grieve -- and two mysterious deaths to investigate. As viewers hashed over details and reconstructed a timeline of events, Diana says they were in full-on speculation mode.
"I've read everything from, you know, foul play -- has someone poisoned them? Could it have been something chemical that leaked from a boat or left by a park visitor? Is it the plants, is it the mushrooms? Could it be disease? Could it be neurological?"
So far, the lab in Wisconsin has ruled out only a few possibilities, says Ranger Michael Saxton, one of the bear technicians who collected the cub's body.
"Rabies is negative, toxoplasmosis is negative as well -- that's just a contagious disease they check for," he said.
Samples from the adult male were sent to a state veterinarian, but unfortunately they arrived a few days too late to be most useful. Dr. Kimberlee Beckmen at the Alaska Department of Fish and Game says the tissue was too decayed to perform most diagnostic tests.
Many bear cam watchers were deeply affected by the deaths, especially that of the spring cub. And there's a tension in the comments, between those who are mourning the bears as you might a pet, and those who see themselves more as citizen scientists.
Back in Maryland, Diana is hungry for more information. But her mind keeps returning to certain moments, like when the sow and her healthy cub returned to where the cub lay dead.