The Ghost Park
Eighty percent of Yellowstone's signature whitebark pines are dead, like these, or close to it.
Credit: Christopher LaMarca

Before that heartbreaking night at the end of July, she was a ghost bear tramping the backwoods shade, a scared specter at her wit's end. She and her three cubs, all woefully thin and eking out a diet from grass and shoots, were so unwell that they wore their winter coats through the full, high heat of summer. In a lean year for grizzlies, they stood last in line, going without a solid meal of deer or elk or the staple of Yellowstone's bears, whitebark pine seeds. Those seeds, rich and fleshy, had grown for centuries on the crowns of the staunchest trees in North America: gnarled, obdurate pines that survived 50-below winters and laughed off killing winds on western peaks. Nothing could slay those trees, neither fire nor ice, until the region started warming around 1980. Now 80 percent of the Rockies' whitebark pine groves stand dead or dying in ghost-gray swaths, and the bears who ate their fruit and kept out of harm's way have bumbled down the hills in search of food. Among their number was the sow with three cubs and teats running dry of milk. With winter two months off, she had to somehow bulk up fast or watch her yearlings starve.

To her credit, she hadn't become a "problem bear," the park officials' term for hundreds of hungry grizzlies who venture into town prowling for food. Though Yellowstone's 600 bears aren't confined to the park itself – they're given free run of the greater ecosystem, an area that stretches from central Wyoming to the forests of northern Montana – there simply wasn't enough alternative food to see all of them through the summer. And while full-grown males have the brawn and bravado to venture off the range in search of meat, a mother grizzly rarely leaves the safety of her turf, lest a wolf pack or another bear kill her cubs. Timidity had its virtues: She wasn't one of the 80 or so bears shot last year while picking apples off a tree or nosing through trash in someone's backyard, or given a lethal injection by U.S. Fish and Wildlife vets for grazing on the bluegrass near a school.

Six weeks before, the first shoe dropped. On June 17, an adult male bear (or boar, as they're called by biologists) killed a veteran hiker who had the wretched luck to cross his path. Erwin Evert, a botanist and and retired science teacher, had spent most of his career studying Yellowstone's flora and had just brought out his life's masterwork, the first comprehensive catalog of plants in the area in more than a hundred years. On his daily hike near Wyoming's Kitty Creek, the easternmost of the park's gateways, he wandered into a copse where a team of federal researchers had trapped and sedated a bear. Alas, they hadn't posted warning signs or waited until the boar was sufficiently roused to pad back into the brush. Dazed and in pain (he'd been darted three times with a chemical cognate of PCP, then had blood, teeth, and hair pulled for study reasons), the bear bit Evert through the skull and skittered off; he was shot two days later by marksmen in a chopper who tracked his radio signal. There hadn't been a bear-caused fatality in the park in 24 years, though given the grim developments of the prior decade – a 10-year run of extreme drought and heat, and a glut of famished grizzlies – the screw was bound to turn. On July 28, it turned again, and this time it wasn't about human error or the caprices of nature's law. This time, it was a taste of things to come.

Sometime after midnight on a streamside slope near the northeast end of the park, the sow and her three cubs entered Soda Butte Campground, drawn by the lingering smell of broiled fish. After trying in vain to pry the tamper-proof lids off food bins and garbage cans, the sow poked her nose under the fly of a tent. She bit the leg of its occupant, Ronald Singer, who managed to drive her off with panicked blows. A short while later, around 2:15 am, Deborah Freele awoke in her tent at No. 11 to find the sow gnawing on her arm. She shrieked and fought back, but the bear bit down harder, snapping bones. By now, there was tumult in adjacent sites, people dashing around and honking car horns in warning, and the sow let go of Freele and ran away. A couple of hours later, rangers and deputies scoured the pitch-dark camp. Near the western end, 600 yards from Freele's tent, they came upon the gnawed remains of a man named Kevin Kammer. Kammer, a medic from Grand Rapids, Michigan, whose lifelong dream was to fish Yellowstone's streams, had been dragged from his tent, killed by several bites, then consumed from chest to groin. There were several sets of prints on his flattened tent – the sow's and at least one of her cubs'.

Over the next days and weeks, all manner of havoc ensued. The media descended from as far away as Finland, asking pointed questions about "killer bears" and the safety of the park's guests. Park Service wardens, who trapped the sow and dispatched her via lethal injection, denounced her as a rogue whose "predatory" act was indefensible but rare. (Her cubs were transported across the state for permanent residence in a zoo.) Test after test was conducted, post-mortem, to establish her motivation. Was she rabid? No. Exotic diseases? None. Maddened by injury or wounds? The federal Interagency Grizzly Bear Study Team, which took charge of the investigation, needed a month to conclude that there was "no clear explanation for the behavior of this bear," though a lucid possibility fairly leaped off her chart. Her weight at the time of death was 216 pounds, or about 80 pounds less than average for a full-grown sow. Like her cubs, called malnourished by the zoo's curator, and countless other bears forced downhill by hunger, she was a forerunner of the turmoil that awaits us all: species pushed to breaking by climate change.