by Cat Urbigkit
The single grizzly bear hair found on Freele’s shoe did not match any of the four bears involved in this incident, indicating that there was a fifth bear at the campground. DNA analysis indicated that the fifth bear was the offspring of the adult female bear that had mauled the three people, perhaps born in a prior year. But there was no evidence this fifth bear was at any of the other attack sites. It is assumed that the fifth bear was a resident of the area, and that Freele had picked up the bear hair sometime during her two-week stay in the area.
What was the trigger that caused the adult female grizzly bear to prey on humans? The usual explanations involve the animal becoming habituated to humans, the bear receiving food rewards from humans, or the bear displaying surprise or defensive behavior in response to a human encounter. None applied in the Soda Butte case. In this case, the bear exhibited predatory behavior, specifically targeting humans as a food source. The investigation team report concluded that the attacks “cannot be clearly explained or understood.”
The female weighed 216 pounds, which is thin, but within the range for adult female grizzlies with yearlings at that time of year. She had a moderate parasite load and was estimated to be between ten and fifteen years old.
The final investigative report noted these issues and added, “It is important to recognize that nutrition can be a contributing factor to stress in wildlife, but in and of itself, nutritional stress is not a sufficient explanation for predatory behavior by a bear on humans.”
Researchers examined the hair, blood, and serum (a component of blood) from the adult female grizzly in an attempt to learn about her habits prior to the attacks. The levels of various isotopes (chemical elements) found in samples can be used to estimate the dietary history of an animal. Hair samples of different lengths can be used to learn if an animal’s food habits changed over time, as revealed during the time the hair was growing. Grizzly bear hair grows at a rate of about 1.5 centimeters per month. Hair samples from the adult female grizzly involved in the attacks included a sample of faded, worn hair believed to have been shed the year before but still clinging to the current hair coat; a sample of new hair from the current growing year; and a mixture of the two. The hair samples were washed and ground, so the isotopes could be examined.
Stable isotope analysis indicated the female bear subsisted primarily on vegetation, with very little meat in her diet—with the result being a marginal level of quality nutrition to a bear already nutritionally stressed by the demands of raising three yearlings. Research indicates that 92 percent of grizzlies in the Yellowstone region consume a higher percentage of meat than this bear, which had relied almost exclusively on plants during the two years prior to the attacks.
Analysis of sulfur isotopes in bear hair, serum, and red blood cells can reveal whether animals are consuming whitebark pine seeds, which are often a preferred food source for grizzlies. Analysis of the sulfur isotopes for this bear indicated that she was not eating these seeds, even though they were abundant in the Soda Butte area.
Isotopes of carbon are used to examine whether an animal has consumed vegetation native to the Yellowstone region, which is associated with a C3 metabolic pathway, or vegetation associated with a C4 metabolic pathway, composed of a group of more tropical plants such as corn, sorghum, and sugarcane. The plants in the C4 group are often associated with livestock feed and dog food, and livestock fed corn or corn-based feed show a C4 signature in their meat. In addition, many human food products contain corn syrup, including granola bars, pop, and many baked and packaged foods. If a bear eats any of these foods (dog food, human food products, livestock, or livestock feed), researchers can detect the C4 signature in the bear’s carbon isotope. Research on the adult female bear involved in the July 2010 maulings indicated that the bear consumed little or no human-related foods, such as human garbage or pet food, during the two years prior to the attacks.
In all three maulings, the bear bit or ripped through the tent fabric or insect screen to reach the victims. One of the victims fought off the bear by punching it, while another made a noise and played dead. The first attack was on a person in a tent with another person and a dog, yet the other two attacks were on lone individuals. No food items or attractants were found in the victims’ tents or campsites, and their fire pits were clean and free from garbage. Contents of the bear-proof food storage boxes did not include anything that would generate odors or aromatic attractants to bears. The bear was unmarked and had never been captured before, and had no prior history of conflicts with humans. There was no evidence the bear had ever consumed human-related foods or had been habituated to humans since she was rarely seen or reported.
“There is no clear explanation for the aggressive, predatory behavior of this adult female grizzly bear in the early morning hours of 28 July 2010,” concluded the final investigation team report on the attacks.
More Fatalities
Fatal attacks on humans by grizzly bears in the Yellowstone region are becoming more common, and in 2011, there were two more human fatalities. One death occurred in July, and park officials noted the offending bear, a sow grizzly, had “acted in a purely defensive nature to protect her cubs. This female bear is not tagged or collared, and does not apparently have a history of aggression or human interaction.” But a month later, the same adult female grizzly bear responsible for that death was linked to the death of a second man. Park officials then killed the 250-pound bear.
The investigative team report provides the chilling details of the first attack in 2011. At 11 a.m. on the morning of July 6, fifty-eight-year-old Brian Matayoshi and his wife, Marylyn, began a hike from the Wapiti Lake Trailhead in Yellowstone National Park’s northern Hayden Valley. It’s a very popular hiking trail in the Canyon area of the park, featuring open thermal areas interspersed with lodgepole pine timber stands. The trails are heavily used by hikers for day trips, as well as by those accessing the backcountry for longer excursions. Hayden Valley is world-renowned for its wildlife viewing, especially for the grizzly bear and bison that are commonly seen here.
One mile into their hike, the couple met another park visitor along the trail. They all stopped at a vantage point overlooking the valley and viewed a female grizzly bear and her two cubs from a distance of several hundred yards. The Matayoshis then proceeded down the trail and into the timber, but soon encountered a dense mosquito population that caused them to rethink their hike. The couple turned around and headed back down the trail they had just traversed, back toward the trailhead. By this time, the female grizzly had left the open meadow where she had been seen earlier and was now close to the trail. By the time the Matayoshis saw the bear, they were within 100 yards of her, so they turned around once again to move away from the large predator.
The sow grizzly saw the couple and gave chase. When the Matayoshis saw the bear begin to move in their direction, they began to run down the trail, yelling. The bear covered 173 yards quickly before hitting Brian, quickly mauling and killing him. Marylyn took cover behind a fallen tree just 5 yards from where Brian was being attacked. After killing Brian, the sow grizzly walked over to Marylyn, picked her up into the air by her backpack, and dropped her back onto the ground before leaving the scene. Marylyn was not physically injured in the attack and went to her husband’s side. When she turned him over, the last breath of his life left his body.
The investigative team concluded that the incident “was initiated by a surprise encounter.” Instead of fleeing, the grizzly sow chased down and attacked Brian Matayoshi, and the report noted: “What possibly began as an attempt by the bear to assess the Matayoshis’ activities became a sustained pursuit of them as they fled running and yelling on the trail. In addition to the unfortunate circumstance of being at the wrong place at the wrong time, a possible contributing factor to the chase that ensued was that the victims ran from the bear while screaming and yelling.” The sow grizzly that had killed Brian Matayoshi was not removed from the population or killed “due to the fact th
at the encounter was characteristic of a surprise encounter.”
The decision not to kill the sow grizzly now known as the Wapiti sow was surely regretted later, when she was found to be involved in a second human mortality a month later.
Fellow hikers discovered the remains of John Wallace, fifty-nine, of Michigan, on August 25, 2011, near the Mary Mountain Trail in northern Hayden Valley. His body had been partially consumed and was covered with debris, typical bear food-caching behavior. Wallace had hiked five miles up the trail, and what exactly happened there will never be known. What is known is that there were two bison carcasses in the area where Wallace’s remains were found, and that there were sixteen bear bed sites around one of the carcasses located near the trail. Nine different grizzly bears, including a sow with two cubs, were seen there by another hiker just a few days before Wallace was killed.
After Wallace’s body was recovered from the scene, investigators found fresh bear tracks in the dust of the trail where the body had been cached.* The tracks indicated an adult grizzly with two cubs had returned to the site where Wallace’s body had been cached. Bloody cub paw prints indicated that an adult female grizzly with cubs “likely fed on or made contact with Mr. Wallace’s body,” the investigative team concluded. DNA testing on bear scat at the site confirmed that it originated with the sow grizzly involved in Matayoshi’s death, which had taken place about a month earlier and 8 miles away. Other evidence at the scene indicated at least one other bear, a male of unknown age and species, had also made contact with Wallace, and that another adult female grizzly bear was also present at the site of the fatality.
Evidence indicates that Wallace had stopped on the trail for some reason at the time of the attack, and had faced a bear and tried to defend himself with his hands. There is no clear evidence indicating what prompted the bear or bears to attack Wallace, according to the investigative team’s report, so it remains unknown whether the attack was defensive or predatory in nature.
The Wapiti sow was captured on September 28 and killed. Her cubs were live-captured and given to an institution to be raised in captivity. The reasons for the removal of all three bears were summarized as:
The Wapiti sow and at least one of her cubs were present at the Wallace fatality site.
The Wapiti sow may have been the bear that attacked and killed Wallace.
Members of this grizzly family were very likely to have been involved in the consumption of Wallace’s body.
The nature of the attack in the Wallace tragedy remains unknown. What is known about both the Matayoshi and Wallace fatalities is that neither of the hikers were carrying bear spray, their best possible defense in an attack. Yellowstone National Park averages about one bear attack on humans each year, but that number doubled in the tragic summer of 2011.
US Fish and Wildlife Service grizzly bear recovery coordinator Chris Servheen questioned whether the four fatal attacks on humans in the Yellowstone region in 2010 and 2011 were random events or evidence of something more. In a presentation delivered to a human–bear conflict workshop, Servheen noted: “There is no evidence to indicate that these were related to any particular factor. The only thing we do know is that human–bear encounter frequency is high because there are so many bears in the ecosystem.”
Surprise Encounters
Shortly after dawn on Thanksgiving Day 2012, a forty-year-old man and his adult sons entered a timbered area along the Snake River in Grand Teton National Park, hoping to harvest an elk. The park’s elk reduction program has been in place since 1950, and allows a limited number of elk to be harvested by special permit. Each hunter undergoes hunter safety and bear safety training prior to entering the field.
All three hunters had bear spray readily accessible, and the father was the first to notice the 500-pound adult male grizzly bear. Soon after it was noticed, the grizzly charged the group of hunters. The father began deploying his bear spray, while his sons both stood at the ready with their firearms. When the bear came within 10 feet of the young men, they both fired their rifles, with three bullets entering the bear and immediately dropping it to the ground. Investigators found a partially consumed and cachedelk carcass just 50 yards away, leading park biologists to conclude that the bear was defending its food source. The bear was estimated to have been nearly twenty years old.
Investigators concluded that the totality of circumstances “indicated that the hunters were forced to make rapid decisions in close proximity to the bear, and they acted in self-defense.” No charges were filed against the men.
This was the first grizzly bear killed by hunters in Grand Teton National Park in the sixty-plus year history of the elk reduction program. The National Park Service noted: “To date, encounters between humans and grizzly bears that resulted in injuries to people are relatively uncommon. However, during the last twenty years as the Yellowstone ecosystem grizzly bear population has recovered and regained formerly occupied habitat (including in Grand Teton National Park), bear maulings have increased.”
Grand Teton has documented six grizzly bear attacks on people since 1994, when a jogger was mauled on the Emma Matilda Lake Trail. Other maulings occurred in 2001, 2007, and 2011. None of these attacks resulted in fatal injuries to humans.
In April 2013, a forty-two-year-old student at Salish Kootenai College, on the Flathead Indian Reservation in northwestern Montana, was mauled by a grizzly sow near the college dormitory. Although injured, the student survived the attack. Tribal wildlife officials declined to take action against the animal, noting that the student had a surprise encounter with the sow and her two yearling cubs, and the sow reacted in a defensive manner.
That same month, an Alaska family had a terrifying encounter with a brown bear on the Kenai Peninsula. The family, a couple and their three children, had been bird watching and participating in a shorebird inventory when one of the children spotted a large sow brown bear approaching them. The family huddled together to appear larger and made noise to deter the bear, but the sow continued her approach. The father, forty-eight-year-old Toby Burke, stepped in front of his family and used a scope and tripod to push back against the attacking bear. The bear bit the scope off the tripod and struggled with Burke briefly before retreating. Burke received minor injuries in the wrestling match. Alaska state troopers arrived on the scene later and were tracking the bear’s movements when it ran at the troopers, who shot and killed it. Officials also received reports of the bear’s strange behavior, such as attacking a moving truck and a telephone pole and swatting at the river. The bear was a twenty-year-old female. Although she had recently emerged from hibernation, she was in good condition, with a layer of fat. Because of her erratic behavior, her remains were tested for rabies, but the results were negative. The necropsy did reveal that the bear was likely blind in one eye and partially blind in the other eye. It is unknown whether impaired vision was responsible for the bear’s behavior.
Numerous grizzly bear attacks on humans were recorded in the Yellowstone region in the summer and fall of 2013. In June, a sixty-four-year-old rancher from Park County, Wyoming, was severely mauled by a grizzly while irrigating on his property outside of Cody. The man’s dog first encountered the bear, which was a sow with cubs. Wildlife officials believe this was a defensive attack, with the man fighting back with his shovel. The man survived his injuries.
In August 2013, grizzly bears attacked two hikers and two researchers in two separate incidents on the same day. In one incident, two hikers had a surprise encounter with a grizzly bear cub on a trail in Yellowstone National Park. The sow suddenly appeared and charged the group, and the hikers deployed pepper spray and escaped from the area with minor injuries. The second incident that day occurred just outside the boundary of Yellowstone National Park, in eastern Idaho. A grizzly bear charged two researchers, knocking both men to the ground and inflicting numerous bites on one of the men. The bear quickly fled the scene, and officials marked this attack up to simply a surprise encounter.
Things were quiet for a month in the Yellowstone region, but in September 2013, a grizzly bear mauled a hunter in another surprise encounter in Wyoming’s Teton Wilderness. The man broke his leg while trying to run from the bear and received bear bites during the attack as well. His injuries were not life threatening.
Future Hunts
In early 2013, the Interagency Grizzly Bear Committee (IGBC)—the consortium of state, federal, tribal, and Canadian resource management agencies charged with the recovery of grizzly bears in the United States south of Canada—endorsed the idea of eventually allowing regulated hunting of grizzly bears as populations recover. It was noted that rather than widespread harvests, the number of grizzlies to be harvested would be in the single digits. Hunting is already allowed in Canada and Alaska.
Idaho Fish and Game deputy director Jim Unsworth stated, “We have bears that are in conflict [with people], and certainly one of the ways that we could deal with that would be to reduce populations through hunting.”
There was an outcry from bear advocates who protested the notion of eventually hunting bears, prompting the publication of an editorial coauthored by Harv Forsgren (regional forester for the US Forest Service and former chair of the IGBC) and Scott Talbott (Wyoming Game & Fish Department director and 2014 chair of the IGBC).
The men noted: “IGBC agencies have collectively and unanimously endorsed regulated hunting as one approach to promote coexistence, management of populations, and reduce conflicts between bears and humans.”