Rebounding Grizzlies Still Face, and Pose, Risks
Yellowstone's rebounding grizzly bear population is an undeniable success. But figuring out how to manage the threatened omnivores--in light of potential food shortages and deadly human-grizzly interactions--isn't so easy.
The grizzlies came over the ridge in the setting sunlight, a female and two cubs. The female's harvest gold coat rippled like it consisted of two layers, one that floated above the other on a layer of oily muscle. from a distance, she looked like a 300-pound bundle of power flowing over the meadow. The cubs ambled along in a teeter-totter gait, roly-poly goofballs as big as St. Bernards, but chubbier. They crossed a grassy bench in Yellowstone National Park's Lamar Valley, skirting a pocket of bison.
Donna and Glenn Vessels watched through binoculars. Donna is in office and furniture supply sales and Glenn is an industrial electrician supervisor. In three days the Vessels, who were in Yellowstone from Troup, Texas, a trip they make twice each year, had seen 22 bears. On this spring evening they had stood in one spot for 90 minutes and seen nine bears, four of which were grizzlies.
"They're just awesome," Donna said. "We tell everyone we can that they need to come here and see it. It's just so inspiring, so beautiful."
"You don't get to see anything like this anywhere else in the United States," Glenn said, then specified the contiguous United States, because they had been to Alaska and seen grizzlies. But Yellowstone is where they keep coming back to.
On the bench, the bison cows stopped feeding, watching the grizzly and her cubs, eyeing the distance between her and their calves. The bears continued, then disappeared over a rise.
"Grizzly bears have this ability to sharpen our senses and our acuity, and they bring us closer to nature by doing that," says Chris Servheen, grizzly bear recovery coordinator for the U.S. Fish and Wildlife Service and an adviser to the Interagency Grizzly Bear Committee--the multi-jurisdictional government effort to recover grizzlies--since its inception in 1983. Servheen has seen countless grizzlies, but still appreciates each encounter. "When you're in bear habitat you have to be more aware of which direction the wind is blowing, what the marks on the trail are, and if you have sight distance on the trail. Bears are magical that way. They bring that heightened sensitivity to us, and we need that in this day and age."
Ever more people are getting to see grizzlies in and around Yellowstone; while more sightings would seem to suggest a healthy population, the bear's future remains uncertain and a source of controversy. Listed as threatened under the Endangered Species Act (ESA) since 1975, grizzly bears in the Yellowstone ecosystem are thriving. Biologists estimate that the population has rebounded from about 200 animals in the mid-1970s to more than 600 known individuals last year. The rise also means the bears are increasingly coming into contact with humans. Just as he thinks we need grizzlies, Servheen believes grizzlies now need us to survive. More grizzly-human encounters inevitably result in more dead bears--and, recently, more dead humans. This past summer grizzlies killed two hikers in the park. In the summer of 2010 there were two fatalities just outside park boundaries. Prior to those killings, there had not been a grizzly-caused death in Yellowstone since 1986.
More bears are dying, too--44 known deaths in 2008 (32 attributable to humans), and 47 in 2010 (40 human-caused), both record years since their 1975 endangered species listing. In 2007 the Bush administration, citing the flourishing population, removed federal ESA protections from grizzlies in the Yellowstone area--designated as a distinct population segment--and declared them recovered. But conservation groups sued, and last year the Ninth U.S. Circuit Court of Appeals upheld a 2009 ruling that returned the bears to the list. In 2007 environmentalists argued that the grizzly's future remained uncertain for several reasons, including the effect global warming and an infestation of mountain pine beetles might have on its traditional food sources. Removing federal protections without understanding what will happen when the bear's diet is greatly diminished, the plaintiffs argued, would be foolhardy.
Even among biologists in the bear recovery arena, there's disagreement about the species' future, and Yellowstone grizzly science has become highly politicized. State and federal biologists who support delisting point to, among other factors, inarguably positive population numbers, growth trends, and reproduction rates. Other conservation biologists, however, contend that trends not accounted for in population figures--like food shortages and proliferating development--pose a danger for even a population as robust as Yellowstone's.
The arguments have grown bitter. Jesse Logan, a researcher and former U.S. Forest Service scientist who studies whitebark pine--whose seeds form an important part of the bear's diet in the Yellowstone ecosystem--believes "the atmosphere is so poisoned it's almost impossible to get an objective view now," and that Congress should order a review by the National Academy of Sciences.
On the other side, Servheen says that environmental groups are trying to demonize the very agencies that brought Yellowstone's bears back from the brink. "For decades we've worked for the conservation of these bears and their habitat, and these environmental groups were nowhere to be seen. And then when [the bears] are recovered, they show up and bray that they need to save the bear from the evil agencies. That's all pretty sad."
Lance Craighead--a conservation biologist who's been involved in grizzly research and debates for a quarter-century and whose father and uncle pioneered grizzly research in America--says the scientific basis for declaring bears recovered entails a lot of uncertainty. "When Yellowstone grizzly bears were petitioned for delisting, the International Bear Association, which is a group of bear biologists worldwide, submitted comments on the delisting proposal that were very precautionary in measure," Craighead says. "They didn't jump on Servheen's bandwagon, and instead pointed out that there were a lot of potential problems--food, population size, climate change. Although Chris likes to believe he represents the majority of bear biologists, I don't think he really does on some issues."
Yellowstone officials believe a grizzly that learns to regard humans as food is a danger too serious to leave on the landscape. That's why they spent weeks trying to find the bear that killed and partially consumed 59-year-old John Wallace this past August on a backcountry trail in the Hayden Valley. Nobody knows how the attack unfolded. Of 13 grizzlies trapped during the investigation, DNA from one female matched that found in a scat sample collected at the scene. Investigators eventually linked the sow to another killing, a month earlier. In July Californians Brian Matayoshi, 58, and his wife, Marylyn, were hiking on the Wapiti Lake Trail when they startled a female with cubs. She moved toward them, and the Matayoshis ran, likely triggering a chase instinct. Marylyn hid behind a small downed tree while the bear attacked her husband, clawing his back and biting his arm and leg, severely damaging his femoral artery. The bear then approached Marylyn, lifted her by her backpack, let go, and left. Brian died from injuries before help arrived. Although park officials determined that the bear acted defensively in a surprise encounter, they euthanized her after hair and scat samples showed that she had been at both crime scenes.
The deaths were the first attributed to bears inside the park in a quarter-century, although the year before two fatal maulings occurred just outside the park. In July 2010 Montana Fish, Wildlife and Parks officers destroyed a sow grizzly that killed a camper. Four bears--an underweight, 216-pound female and her three yearling cubs--entered Soda Butte campground in the early morning hours, though the campers hadn't left out anything that would attract grizzlies. There they attacked sleeping campers, killing one: Kevin Kammer, 48, a father of four from Grand Rapids, Michigan, who was found 30 feet from his tent and partially consumed. When the female returned to the scene, officials trapped and euthanized her; they sent the cubs to zoos. A necropsy of the bear showed a parasite load that, combined with the demands of cub rearing, may have contributed to the sow's low weight. She had probably lived within a few miles of the campsite during her adult life, and sophisticated tests showed that for the previous two years she had eaten an almost exclusively vegetarian diet.
A month earlier a grizzly killed Erwin Evert, a 70-year-old botanist from Chicago who had spent years hiking the wooded ridges of Shoshone National Forest on Yellowstone's eastern edge. Although the details are unresolved, Evert encountered a bear that, just hours earlier, Interagency Grizzly Bear Study Team biologists had trapped, sedated, and fit with a radio collar. It killed Evert with a bite to the head, and Wyoming wildlife officials later shot it.
Four deaths in two summers fueled public interest in grizzly attacks. The popular media piled on, including a fact-challenged article in Men's Journal [[LINK Men's Journal: http://www.mensjournal.com/who-pissed-off-the-bears ]] that all but concluded that starving bears were streaming from the park to eat people. Statistically, the incidents were freak occurrences. Since the 1930s, as Yellowstone Park visitor numbers have skyrocketed from 300,000 annually to 3 million, bear-inflicted injuries to humans have fallen from 175 per million visitors to fewer than one per million.
As rare as they are, gory maulings color public perceptions, though almost all experts dismiss any notion that hungry bears are hunting humans. "There's no connection between any of these attacks and food sources," says Servheen. "We have no reason to believe that bears are seeking people out to eat them in the Yellowstone ecosystem. I think it's irresponsible for people to make conclusions like that. That's crazy."
Craighead agrees. "If food shortage was a real driver, it would be more likely happening early in the spring and late in the fall, when they're urgently looking for food," he says. "Since these happened early in summertime it's not as likely that would be one of the main causes. This doesn't set off any alarm bells for me."
While people aren't likely to be increasingly part of the menu, different foods have come to play a pivotal role in the legal battles surrounding the level of protections afforded to grizzlies going forward.
or decades grizzlies saw humans as a source of food. They concentrated at park dumps, where the waste from Yellowstone's massive tourism stream was left in piles for them to sift through. The dumps attracted so many bears that park officials even provided bleachers for the throngs of visitors who watched the animals scrounge and battle over refuse. Entire generations of bears became dependent on the dumps.
In 1959 John and Frank Craighead launched an intensive, pioneering study of Yellowstone's grizzlies. The brothers tranquilized, measured, collared, and tracked them. By then park officials had started worrying that feeding bears at open dumps was not consistent with their mandate to preserve wildlife in a natural setting. The Craigheads concurred, but a disagreement boiled over about how quickly to close the dumps.
The Craigheads were adamant that they should be phased out slowly so as not to create a food shock. But park officials decided to move quickly. Between 1968 and 1971 all the park's dumps were shut down and sanitized. The grizzlies fared about as the Craigheads had predicted. Human-bear interactions jagged upward as grizzlies spent more time in campgrounds. From 1968 to 1971 at least 140 grizzly deaths--about half of the Yellowstone ecosystem's population, the Craigheads estimated--were attributed to human causes. Grizzly populations in the park began a perilous decline. By 1975, when the bears were given ESA protection, their number in the park and its surroundings ranged from 136 to 312 individuals.
Those that did survive learned to be general omnivores again. Some had lived their whole lives without ever visiting the dumps, and their offspring prospered. Brown bears, of which grizzlies are a subspecies, are generalists. Which is why they're the world's most widely distributed bears, existing in conditions as varied as the salmon-rich estuaries of Kodiak, Alaska, and the protein-poor peaks on the Pakistan-Afghanistan border. Brown bears survive in Mongolia's Gobi desert and in Europe's remnant forests. They adapt to such varied conditions by learning to eat what's available. Historically, 60 percent to 70 percent of female grizzlies' diets in Yellowstone have consisted of plants and insects; the number is 30 percent to 50 percent for males. And the bears are brilliant at recognizing which food is available during specific times of the year, and from year to year.
In the courtroom, two specific food sources--whitebark pine seeds and Yellowstone cutthroat trout--formed the basis of a lawsuit that reversed the Bush administration's 2007 decision to delist Yellowstone grizzlies. "It seems paradoxically clear that the bears are not out of the woods yet," says Jeff Welsch, spokesperson for the Greater Yellowstone Coalition, which filed the suit that in 2009 returned Endangered Species Act protections to the grizzlies.
There's no argument that a sizable percentage of Yellowstone's grizzlies rely on whitebark pine seeds; in a bounteous year, for a significant number of bears, pine seeds might provide 90 percent of nutrition in the fall. And no one disputes that whitebark pines are dying throughout the northern Rocky Mountains. Climate change, disease, and the mountain pine beetle--all three inextricably linked--are driving the destruction. As the trees die, Welsch fears bears in the park's interior that depend heavily on the nuts will forage for other foods at lower elevations, pushing out toward park boundaries. The ripple effect could force other bears into more marginal--human-occupied--habitat. "When you have diminishing natural food sources bears start looking in places we don't want them to look," he says, recalling the dump closures. "Bear managers have done a fine job of bringing [grizzly recovery] to this point--it's a great success story--but until we're sure that they're able to adapt to a rapidly changing world, we'd better be careful with them, because grizzlies are Yellowstone."
The whitebark pine's extinction, should it occur, will happen gradually, Servheen counters. Besides, he points out, grizzly populations increased approximately three percent a year over the past 24 years, even though only half of those years produced bumper crops of whitebark pine seeds.
Meanwhile, populations of Yellowstone cutthroat trout, indigenous to Yellowstone Lake and its drainage, have crashed. Everyone agrees that lake trout, illegally introduced, are largely to blame. In Clear Creek, once an important cutthroat spawning artery--and once a protein source for some bears--cutthroat numbers slid from 70,105 in 1978 to just 538 in 2007. The same picture draws itself all over the drainage. Because lake trout spawn in deep water, they're beyond reach as a substitute protein.
And yet, says Servheen, it's not the end for grizzlies. "Cutthroat trout was a very, very, very minor part of the diet of very few bears in the Yellowstone ecosystem," he says. "Less than 10 percent of the population ate cutthroat trout for a couple weeks when they were available." Now those bears have switched to preying on elk calves, Servheen explains. "That's what makes grizzly bears grizzly bears--their ability to have such a diversity of diets."
The Ninth Circuit Court of Appeals based the bear's re-listing primarily on the whitebark pine uncertainties. Cutthroat weren't cited as a major concern, nor were environmentalists' assertions that regulatory mechanisms weren't adequate to protect the population should it begin spiraling downward.
The search for protein can also lead to grizzly mortalities. During hunting season, bears can be drawn outside the park onto national forests lands, where elk hunters leave tons of gut piles and carcasses every fall. Unfortunately, encounters with hunters are one of the leading causes of death for bears. Whatever foods replace cutthroat trout and pine nuts have to pack equivalent nutritional value without significantly elevating the cost of securing those calories, Jesse Logan argues. He acknowledges that large male grizzlies can take over wolf-killed elk carcasses but notes that those same males will kill females and cubs that try to sneak a bite. "Meat is a very dangerous, very high-cost food source to exploit. And even more dangerous than a boar grizzly is a hunter armed with a 30.06."
Indeed, one study found that grizzlies are twice as likely to die at the hands of hunters during poor pine seed years.
Back in the Lamar Valley, the sun slipping even lower, the sow and cubs that had thrilled the Vessels suddenly reappeared. Despite the uncertainties and disagreements, nobody can deny that this population has turned around from the days when its numbers plunged. These bears--and two other grizzlies the Vessels had seen that evening--are prime examples of what thorough management can do to recover a species teetering on the brink.
As the bears crossed the green bench, the bison had enough--they gathered and trotted away. One cub stood on its hind legs, watching them, then dropped and scrambled to catch up to its mother. The sow continued downslope. About a mile to the east, in the direction she now traveled, a boar grizzly, dark and massive, grazed on vegetation. Although she could not possibly see the big male, the sow angled sharply north, toward the river bottom, working her way around him. Like most of Yellowstone's grizzlies, she knows how to traverse the landscape between banquets and threats, and how to make the most of her world. Within a few moments, she and the cubs had disappeared behind a fold in the landscape, into the wildness of Yellowstone.
Even if these cubs never leave the park, a place we once dreamed would protect wildlife in a semi-Edenic state, their future remains inextricably intertwined with ours. If grizzlies can continue to react and adapt to a rapidly changing world, there's hope for these young bears and their offspring. But if we continue feverishly feeding climate change and altering the land too quickly, the remarkable success of Servheen and others involved in the recovery effort could suffer--and the bears we see roaming the Yellowstone ecosystem today may represent the high tide of healthy grizzly populations in modern America.
This story originally ran in the March-April 2012 issue as "Grizzly Encounters."
Scientific name: Ursus arctos horribilis
Identification: Males stand seven feet tall and weigh 400 to 600 pounds; females can reach 350 pounds. Color ranges from light brown to nearly black. Besides their greater size, the grizzly's concave face, high-humped shoulders, and long, curved claws differentiate it from black bears.
Range: Occurs from Alaska, south through western Canada, and into Washington, Idaho, Montana, and Wyoming.
Behavior: Grizzlies spend much of their lives alone, except when mating and rearing young. Their diet is largely green vegetation and insects; meat comes primarily from carcasses, though a grizzly will occasionally take down elk or moose calves. Hibernates for five or six months a year, starting in October or November.
Conservation status: Federally listed as threatened since 1975. In the early 1800s an estimated 50,000 grizzlies roamed between the Pacific Ocean and the Great Plains. Today roughly 1,700 of the bears live in the Lower 48 states, although, thanks to conservation efforts, population numbers are on the rise.