Investigating a grizzly bear crime is fundamentally about two things: finding the bear responsible, and figuring out the bear’s motivation. The first question is a matter of old-fashioned police work, very similar to the kind done in human investigations; the second, which determines whether a bear will be released, relocated, or euthanized, involves an expert in bear behavior—a forensic psychiatrist crossed with a veterinarian.
Wildlife biologists like Kerry Gunther help the park's crime-scene investigators by speculating on a bear's emotional state. Based on the evidence at hand, he tries to determine whether a given act of bear aggression might have been a natural behavior—the result of being startled while feeding on an elk carcass, for example, or seeing someone approaching her cubs. If a bear appears to have followed a hiker down the trail instead of backing off, or if it attacked campers while they were asleep, that would be more unusual—the result, perhaps of a deranged grizzly mind.
In a mauling case like that of John Wallace, in which there are no living (human) witnesses, sorting out these categories of bear aggression can be especially vexing. But there's one piece of circumstantial evidence that almost always leads to euthanasia: a half-eaten corpse. Under normal circumstances, the grizzly diet in Yellowstone is about 60 percent vegetarian—roots and nuts, with the remainder coming from pocket gophers, trout, elk, and bison. If the rangers have good reason to believe that a bear killed a human being and then consumed his body, that bear's behavior will be deemed unnatural—and its crime a capital offense.
That's what happened in 1986, when the Park Service sent out a team to investigate the mauling death of 38-year-old mechanic and amateur photographer William Tesinsky. Tesinsky went to Yellowstone to get a photograph of a bear, but he got too close to a very hungry one known to bear managers as No. 59. As described in Scott McMillion’s book on bear attacks, Mark of the Grizzly, rangers arrived on the scene to find his tennis shoe, and a piece of his leg in No. 59's sharp teeth. When they radioed back to headquarters, the Yellowstone bear manager gave the order to kill.
After they shot No. 59 to death, rangers reconstructed the scene. Tesinsky’s tripod was thoroughly mangled, with grizzly hair and blood mashed into it, and his camera’s focal length was set for a photo taken 30 to 50 feet from its subject. Under most circumstances, bear managers would deem such an encroachment a natural cause of aggression for a bear. Add in the fact that it was the autumn of a bad food year and No. 59 would have been desperate to put on weight, and it seemed the mauling might have been an unfortunate accident. But No. 59 was caught eating the corpse, so she had to go.
The zero-tolerance policy for man-eating bears invites an obvious question, though. Once a bear kills someone, whether it's out of some wild-animal psychopathy or a natural inclination to defend her young, why wouldn't she eat the corpse? Everyone agrees that it’s natural for grizzlies to eat carrion—they’re scavengers, after all. When I ask Servheen whether grizzlies can get "a taste for human blood"—whether a grizzly that starts eating people-meat will desire it endlessly—he dismisses the idea. "That’s for horror stories in movies," he says. "Bears don’t get a taste for human blood. There’s no studies that show that."
No studies show it, in part because every time a bear eats someone, they kill it. Not that it’s something that would ever be studied—biologists would never want to take the risk of keeping a bear that had eaten a person in the greater bear population. "We don’t want to test whether bears really get a taste for people,” Gunther explains. "The public wouldn’t appreciate us using them as subjects." That's for horror movies, but it seems like even the bear biologists think there might be some truth to the campfire legends.
On the Mary Mountain trail in August, Gunther and the other rangers were working as fast as they could to gather information from the half-eaten corpse of John Wallace. It was a race against the setting sun, and they were worried about agitated grizzlies in the area. They knew, at this point, that a bear had been feeding on the body, but they didn't know for sure what killed him. Wallace was in good shape with no history of illness, but he was almost 60. Other causes of death—such as stroke or heart attack—were not out of the question.
It was one ranger’s duty to keep a watch out, while the rest of the team scoured the crime scene. But the hunt for clues was frustrating. If only someone had found the body on the day that Wallace was killed, as opposed to the day after, evidence might have been easier to come by: The saliva from the bite wounds on Wallace’s body would have been better preserved, and hairs from his attackers might still have been present on his clothes and camping equipment. But there had been a massive storm on the night of Aug. 25, arriving about eight hours after Wallace was killed. Pounding rain and even some hail had obliterated the first set of tracks and may have washed away other clues as well.
Despite the weather, Gunther could tell there was still much to be discovered. The first thing he saw was a scrap of cloth from Wallace’s boxer shorts sitting in a pool of blood. As they got closer to the body, the team of investigators found Wallace’s hat, bandanna, and whistle. Then they followed the path of matted grass toward the body until they spotted something else—two dark, loose piles of animal droppings about 4 inches in diameter, situated on either side of Wallace's hat and bandanna. This is where a bear biologist like Gunther comes in handy—he knows a pile of grizzly bear scat when he sees it. And if you're looking for a bear's DNA, her excrement is a great place to find it.