Are Hungry Bears in Yellowstone Attacking Humans for Food?

For 24 years, from 1986 until 2010, there were no mortal encounters with grizzlies in Yellowstone National Park. But four deadly incidents over the past two summers have hikers on edge, reigniting the fierce debate over bear management.

May 7, 2012
Outside Magazine
Grizzlies in Yellowstone

Grizzlies in Yellowstone    Photo:Illustration by Edel Rodriguez

WHEN THEY DROVE through the entrance to Yellowstone National Park on July 5, 2011, Brian and Marylyn Matayoshi, of Torrance, California, were handed a newspaper—just like the other 3.4 million people who entered the park last year. The paper included, among other things, advice about what to do in the event of an encounter with a grizzly bear.

The following day, when the couple decided to hike a portion of the popular 16-mile Wapiti Lake Trail in the park’s Hayden Valley, they would have walked right by two wooden signboards. One, in large, bold letters, read WARNING: BEAR FREQUENTING AREA. The other read DANGER: YOU ARE ENTERING BEAR COUNTRY and displayed information about how visitors should react if they come upon a bear. The recommendations included “If a bear charges, stand still, do not run” and “Bear pepper spray is a good last defense.” The Matayoshis were making their fifth visit to Yellowstone; they’d never seen a grizzly in the park. 

Despite the recommendation, neither Brian, 58, a retired pharmacist, nor Marylyn, also 58, carried pepper spray when they started hiking the Wapiti Lake Trail around 10 a.m. on that bright 70-degree morning. About a mile into their walk, a hiker coming toward them pointed out what looked to Marylyn like brown boulders about a quarter-mile in the distance. These were, it turned out, a grizzly sow and its two cubs. The Matayoshis stopped to watch the bears for a few minutes. Marylyn even took some photos: three brown dots on a vast green landscape. 

The couple continued up the trail, hiking onto higher benches through scattered lodgepole forest. But another half-mile in, Yellowstone’s brawny mosquito population descended with virulence, and the couple decided to turn back. Unbeknownst to them, while they were hiking, the grizzlies they had seen earlier had moved closer to the trail and were heading right toward them. 

When Brian spotted the bears again, only about 100 yards and a thin band of trees separated them. The Matayoshis did an about-face and started back up the trail, away from the grizzlies, glancing back over their shoulders. Marylyn saw “the bear’s head pop up” and alerted Brian. 

The sow “started coming toward us,” Marylyn later told National Park Service investigators, “and Brian said, ‘Run!’ We were running down the trail.”

Other hikers in the vicinity heard the couple screaming as they fled. The Matayoshis sprinted, with the sow in pursuit. Marylyn said the cubs followed their mother, growling. The Matayoshis made it 170 yards before the grizzly knocked Brian down from behind and delivered a powerful blow to his forehead. While Brian lay prone, the grizzly clawed his body and bit his right leg several times. 

Marylyn ducked behind a small downed tree about five yards away and hid. She peeked up once and saw the bear standing over Brian’s inert body, staring at her. The bear walked over, and Marylyn dropped to her stomach, covering the back of her neck with her hands. The sow sank its teeth into her daypack and lifted her off the ground, then dropped her. Then the bear was gone, along with its cubs. Marylyn scrambled to her husband’s aid, trying to tie her jacket in a tourniquet around his leg to stop the bleeding. Brian took a deep last breath, and Marylyn realized he was dead, succumbing to either the blunt-force trauma of the attack or blood loss from a severed femoral artery. 

In the days that followed, Yellowstone officials and bear managers decided that the sow had reacted defensively, protecting its cubs. They decided to leave it in the wild. 

THE ATTACK ON Brian Matayoshi is part of a recent spate of human deaths in and around Yellowstone that has park officials and wildlife managers in Wyoming, Montana, and Idaho worried. For 24 years, from 1986 until 2010, despite rapidly escalating tourist numbers, there were no mortal encounters with grizzlies in the park.

Two of the Yellowstone-area victims were partially eaten, a fact that has led to sometimes irresponsible speculation in the media about hungry bears killing people for food. That speculation has been fueled by a recent federal-court ruling involving uncertainty about key grizzly food sources due to global warming, specifically reductions in whitebark pine seeds and cutthroat trout. Indeed, a breathless Men’s Journal article in April 2011 implied that starved grizzlies might already be venturing out of the park to eat people.

But all parties interviewed for this story stated their belief that the partial consumption by grizzlies of two people in two years was not connected to a decline in food sources, and that a mere two incidents do not provide compelling evidence of a hungry bear population altering its behavior to hunt humans. Understanding this requires taking a close look at a number of issues, starting with the incidents themselves. 

In July 2010, Ronald Singer, a 21-year-old from Alamosa, Colorado, was camping with his girlfriend in the Soda Butte campground, on U.S. Forest Service land, a few miles from the northeastern corner of Yellowstone, when his tent suddenly shifted several feet and an animal bit his calf through the fabric. Singer punched at the snout digging into his leg, and the attack ended. Singer, his girlfriend, and her family rushed to nearby Cooke City to alert authorities. Meanwhile, in another tent at Soda Butte, 58-year-old Deb Freele, from London, Ontario, had also snapped awake and felt teeth “grinding into my arm.” 

“I realized, at that split second, I was being attacked by a bear, but I couldn’t see it,” Freele told the Associated Press the next day from her hospital bed. She screamed. “And then it bit me harder, and more. It got very aggressive and started to shake me.”

Freele switched tactics, playing dead, and the bear left her, though not before breaking her arm. Park County sheriff’s deputies and a game warden from the Montana Department of Fish, Wildlife, and Parks arrived shortly after and began clearing the campground. While doing so, they discovered the body of Kevin Kammer, 48, a father of four from Grand Rapids, Michigan. Kammer had been camping alone about 600 yards from where the other attacks occurred. His body had been dragged 25 feet from his tent and partially eaten. 

The bear that killed Kammer came back the next day, looking for more food. It brought along three cubs. Using part of Kammer’s tent as bait, state officials set a culvert trap that easily caught the animal. It was held in the trap until the cubs could be captured. Then it was euthanized. The cubs were placed in a zoo.

The sow was thin but within the range of normal for a female bear with three cubs at that time of year. Sophisticated tests indicated that it existed almost exclusively on a vegetarian diet. The bear had probably lived in the area most of its life and had never been in trouble with humans before. Nobody could explain why it had chosen to stalk the campground for human prey. 

The second incident involving bears consuming human flesh occurred inside the park last year, several weeks after the Matayoshi attack. On August 26, five miles up the Mary Mountain trail in the Hayden Valley—in fact, just eight miles from where Brian Matayoshi died—hikers stumbled onto the remains of John Wallace, a 59-year-old Michigan man. Investigators found his daypack nearby, waist belt unclipped and zipper open. His lunch was uneaten. Bite marks on Wallace’s forearm and hand indicated that he had tried to defend himself. At least one bear had fed on his corpse. 

Wallace had visited Yellowstone before and was an experienced backcountry hiker. When offered standard bear-safety literature by Yellowstone personnel as he checked into the Canyon Village campground on August 24, Wallace reportedly replied that he didn’t need it. He was, he said, “a grizzly bear expert.” 

Three days before Wallace died, another hiker spotted nine grizzlies near a bison carcass about a mile and a half from where Wallace’s remains were found. Park officials investigating his death counted 16 grizzly day beds near the attack site. Hair and scat found nearby contained DNA from four bears. Here’s where the investigation revealed a surprise: one of the DNA profiles matched the sow that killed Brian Matayoshi. One of that bear’s two cubs also left DNA at the Wallace scene. 

“We don’t know what role she played, whether she was the attacking bear or the feeding bear,” says Kerry Gunther, bear-management program leader for Yellowstone park. “It’s possible that she was just in the wrong place at the wrong time and her DNA was there. To err on the side of safety, we decided to remove her.”

Trapping efforts began immediately. On September 28, a healthy 250-pound, six- or seven-year-old sow was caught. DNA evidence in hand, park officials decided to euthanize it. The cubs were captured and sent to a zoo. Subsequently, DNA from another bear was found near where Wallace was killed, but the animal had gone into hibernation before the test results could be confirmed. At press time, park officials were still deciding whether to eliminate that bear, which had been radio-collared, when it emerges from its den. 

Both fatalities inside the park were treated as anomalies, according to Gunther, and statistically they are. So was an earlier fatal attack, a controversial encounter that happened in the Kitty Creek drainage, just outside the park’s eastern boundary, in June 2010, when a 70-year-old botanist and experienced backcountry hiker named Erwin Evert came upon a grizzly that researchers had just tranquilized, radio-collared, and released. The research team had put up warning signs about the bear but removed them as they left the drainage. Evert was found dead from a bite to his head.

Evert’s family has filed a lawsuit against the federal government, claiming that the warnings weren’t adequate. (There’s some question about whether Evert purposely hiked into the area, having seen the signs earlier.) Meanwhile, after unsuccessful trapping attempts, officials tracked the grizzly that killed Evert and shot it from a helicopter.

WHY THE SUDDEN SPIKE in fatal bear encounters? Part of the problem, believes U.S. Fish and Wildlife Service grizzly bear recovery coordinator Chris Servheen, who has spearheaded the government’s efforts to bolster bear populations for over a quarter-century, is messaging. One of Servheen’s great vexations is an inability to make the millions of Yellowstone visitors pay attention to a few basic rules of travel in grizzly country: don’t hike alone, make lots of noise, carry bear spray, and, if a grizzly still keeps coming, drop into a prone position. Wallace, Evert, and the Matayoshis had all, on more than one occasion, seen grizzly literature or signage. Yet none carried bear spray, and Evert and Wallace were hiking alone—acts that ignore official warnings and recommendations.

“My candid opinion is that we have not been very successful at communicating to the public,” Servheen says. “We produce a lot of information, but we don’t get that information to people.”

That, he says, aggravates the larger issue—a growing grizzly population in a location increasingly visited by humans. “We have more bears in more places, so the encounter frequency is going up, the probability of running into a bear is going up,” Servheen says. “We have grizzly bears occupying places they haven’t occupied in 100 years.”

In almost every way, grizzly recovery in the Yellowstone region has been a shining success. Grizzly numbers have grown from estimates ranging as low as 136 bears in 1975, when they were assigned threatened status on the Endangered Species List, to 602 in 2010. (Throughout the lower 48, grizzly numbers have bounced back from about 550 in 1973 to 1,700 today.) This has met all population goals set by the Grizzly Bear Recovery Plan drawn out by Servheen. 

“The third-highest count of females with cubs on record was in 2010, so reproduction continues to increase,” says Servheen, who, though often dressed in Carhartts and flannel shirts, projects the measured calm of an effective high school principal. “They’re a fully recovered population.”

Yet, in November 2011, the Ninth Circuit Court ruled that Yellowstone’s grizzlies should not be delisted. The decision settled a lawsuit brought in 2007 by the Greater Yellowstone Coalition—with amicus support for the court from the Natural Resources Defense Council—after the Bush administration tried to delist the Yellowstone population. At the heart of that lawsuit was an issue that is also part of the mystery of why grizzly attacks on humans are increasing: Are Yellowstone’s bears running out of food sources? 

At issue is the whitebark pine, a species that produces cones full of seeds. Red squirrels collect and hoard the seeds in caches, which grizzlies rob and gobble. In good seed-production years—sometimes as often as every other year—some of Yellowstone’s grizzlies might derive as much as 90 percent of their autumn protein intake from seed middens. But whitebark pine trees are dying en masse, victims of mountain pine beetle infestations and white pine blister rust exacerbated, many scientists believe, by global warming. Grizzly managers and conservation groups don’t agree about the implications of that decline, and the disagreement has become divisive. 

Federal and state game-management agencies—specifically the U.S. Fish and Wildlife Service; Montana Fish, Wildlife, and Parks; Idaho Fish and Game; and the Wyoming Game and Fish Department—want grizzlies delisted because they fear that, as has happened with wolves, extending endangered-species protections for grizzlies even after numerical goals have been reached will provoke ill will among local ranchers and hunting groups. Ranchers call managers to remove bears that kill or threaten livestock. Hunters have surprise encounters with grizzlies in the field, feel vulnerable, and shoot them—or they mistake grizzlies for black bears, a game species.

“The rush to delist is so strong, there’s been a lack of truly trying to deal with this issue in a scientific manner,” says Jesse Logan, a former Forest Service researcher. Logan says that 95 percent of whitebark pine trees in the Yellowstone area have been impacted to some degree by beetles and that 55 percent have “suffered severe mortality.” “It’s devastating,” he says. “Unprecedented in what we consider the historical record.

“Right now, what we really need is an external review from an unbiased source,” Logan continues. He suggests convening a panel of the National Academy of Sciences

Servheen and his colleagues with the Interagency Grizzly Bear Study Team believe that, while whitebark pines will most likely continue to die off, the changes will happen slowly enough for grizzlies to adapt. Whitebark pines have been declining for decades, Servheen points out, and still the grizzly population has grown steadily. Servheen also cites the Yellowstone Lake basin, where the illegal introduction of predacious lake trout has resulted in precipitous declines in cutthroat populations, virtually eliminating them as a food source; some grizzlies there have shifted their focus to prey more on elk calves, swapping protein sources.

“Grizzlies food-switch,” Servheen says. “They have the ability to eat things when they’re available and then go to something else when they’re not. If you wanted to design an animal that would be optimally resilient to global warming, it would be omnivorous, an animal that lives in a wide variety of elevations and aspects, and one that is very adept at food switching. The animal you designed would look a lot like a grizzly bear.” 

A significant number of conservationists, most vocally Natural Resources Defense Council senior wildlife advocate Louisa Willcox, think Servheen’s explanation is too simplistic. Logan agrees, noting the increased risk grizzly bears face when switching to other food sources. “What specifically are the alternative foods? What is their seasonal and spatial abundance? How do they compare in nutrient value, both in quantity and quality, with whitebark pine nuts? And what is the risk to the bear?” A red squirrel defending its pine-seed cache, Logan points out, is not much risk to a sow grizzly with hungry cubs to feed. A boar grizzly defending an animal carcass is a different story. 

Whichever side of the debate they come down on, most experts agree that increasing bear populations and increasing human visitation to Yellowstone will almost certainly result in more run-ins between people and grizzlies. Still, as gruesome as four human deaths in two years may be, the fact remains that human-bear encounters are far deadlier to bears than to people. Between 2003 and ’06, an average of about 16 Yellowstone-area bears were killed by people annually. Over the past four years that average has leaped to 38, the result of federal or state wildlife agencies removing bears or of increased encounters with hunters. 

A number of grizzlies that live near park boundaries are more likely to be found in adjacent national forests and private lands during the months overlapping big-game hunting seasons in Montana, Wyoming, and Idaho—largely because each autumn hunters leave an estimated 370 tons of gut piles and field-dressed carcasses lying on the landscape. Servheen thinks that generating buy-in from outfitters and area ranchers is crucial to the bear population’s continued health. Moving the goal line—as Servheen thinks the Ninth Circuit ruling does—will disenfranchise the people whose cooperation is most vital, locals who could easily revert to a shoot-shovel-and-shut-up mentality. 

“Recovery is not dependent on environmental groups. And it’s not dependent on federal judges,” Servheen says. “It’s dependent on what people who live and work in bear country think about grizzlies. The greatest gains are to be made with people who might not like bears, the hunters out there looking through their scopes. Those are the people who are going to make or break conservation for grizzly bears.”

EIGHT MONTHS AGO, on a cold November day, Jim Halfpenny tromped through eight inches of snow near the Lamar River in Yellowstone’s northeastern corner, following a set of pigeon-toed grizzly tracks. The tracks were at least a day old and the chances of bumping into the bear that made them slim. 

Halfpenny, a world-renowned tracker and naturalist, came to Yellowstone in 1971, fresh from the Vietnam War, and established the first winter concession in the park, running a cross-country-skiing operation out of Old Faithful. He saw his first grizzly the next spring, in the Hayden Valley, and remembers trembling while trying to photograph it. “There’s a magic about grizzlies I can’t explain,” Halfpenny says. “Bears are wild, and what I like is wild.”

Halfpenny began studying bears, walking around the backcountry and recording contact with them. Then he started leading field courses to observe them, trying to broaden understanding of the animals. “I got to spend a lot of time with grizzlies,” he says. “I got to spend a lot of time with my students up close and personal with bears. Many years ago, we’d sit in the Hayden Valley or the Lamar all day within 50 yards of an old sow, watching her dig, and when she moved over we’d move in to see what she had been digging. People would have a tizzy if we did that now.” 

While there are no simple answers, it’s worth noting that bear encounters need not end in tragedy. Halfpenny, who has been charged by grizzlies numerous times but never injured, thinks that understanding a bear attack is largely a function of understanding bears. “If a bear starts watching you, keeping its eyes on you, turning to face you, those are nervousness signs,” Halfpenny says. “If the bear changes its behavior, moves away from you, that’s a sign of nervousness. If a bear looks straight at you and drops its head, that’s an aggressive bear. 

“You never run, and you never turn your back on a bear. Keep an eye on the bear, but don’t challenge it. Look at its shoulder. Try to back your way out. Talk to the bear and see how it responds. If your voice is escalating the situation, shut up. People want a single answer about how to deal with grizzlies, but each bear is an individual, and you never know which side of the bed he woke up on.”

Not everybody, Halfpenny understands, can know bears as well as he does—which is partly why he’s trying to teach people about grizzlies. He thinks we can all be more prepared in bear country—not by studying intricate details of bear behavior but by understanding ourselves. “Somebody who’s going to hike in grizzly country has to decide ahead of time how they’re going to act. If you’re going to carry pepper spray, you should know how to use it,” Halfpenny says. A study of 20 years’ worth of human-bear encounters in Alaska found that pepper spray was effective in stopping 92 percent of grizzly charges. 

“You have to know in advance—really know this—that if a bear comes, you’re going to drop into that bear-defense position,” Halfpenny says. 

Trudging through the snow, Halfpenny followed the blue-shadowed grizzly tracks to where the land dropped steeply toward the Lamar River, in a seam bristled with dark timber. This summer, Halfpenny and his students will likely be watching this bear and dozens like it as they wander Yellowstone’s wild landscape. Grizzly managers and park officials will be watching, too, keeping a close eye on what happens between the resurgent bear population and the ever growing throngs of park visitors. Servheen and his colleagues will endeavor to communicate more effectively. Their success, they know, will almost certainly depend on people getting the message—from park officials and from the grizzlies themselves.

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