IN THE FALL OF 2009, Taylor Mitchell, a 19-year-old folksinger from To­ron­to, was touring the Maritime Provinces of eastern Canada in support of her critically acclaimed first album, For Your Consideration. With a free afternoon between gigs in Nova Scotia on October 27, she pulled into Cape Breton Highlands National Park and set out along the heavily visited Skyline Trail. The temperature was in the high thirties; birch and maple leaves would have crunched beneath her feet.

Taylor Mitchell Taylor Mitchell

Glowing eyes of eastern coyote hunting at night.

Less than half a mile ahead of Mitchell, two other hikers were making their way along the boreal trail. When a pair of coyotes came padding toward the men, they paused. Surely the animals would turn tail and disappear into the forest. In fact, no: This pair acted fearless, and came closer and closer to the astonished hikers. When a mere 20 feet separated man from canid, one hiker raised his camera to his eye. The resulting photograph would soon become crucial evidence: Within minutes of the shutter click, the coyotes, who had moved down the trail, intercepted and viciously set upon Mitchell. The singer screamed and may have tried to run, an action that would have exacerbated the attack. Drawn by the commotion, hikers from both directions raced to her side, scared off the coyotes, and dialed 911. But Mitchell was already in critical condition. Airlifted to the hospital with bite marks covering most of her body, she died the following day.

Cape Breton Highlands rolls over 366 square miles of elevated forest and open swale. About 100 eastern coyotes make their living inside the park, though the animals have inhabited it only since the 1980s. The coyote evolved as a hunter of small mammals in the Great Plains, but within the past half-century the species has expanded its range to the entire lower 48 and to every Canadian province. "We're among the last places to get them," says Derek Quann, the park's resource-conservation manager. In Quann's park, the animals eat hare and small rodents but, working in groups in the deep snows of late winter, have also been known to take down 1,200-pound moose an astonishing feat, considering that western coyotes neither hunt in groups nor prey on anything larger than sheep or calves. Wolves, however, routinely do both, which raises the question: What exactly is an eastern coyote?

MITCHELL'S DEATH only the second fatal coyote attack recorded in North America sent park managers into a scramble. What had provoked such bold behavior? Was the public safe? After the attack, employees closed the Skyline Trail and shot two coyotes. Analysis of the animals' stomach contents confirmed that these were indeed the antagonists. Necropsies found that the coyotes weren't rabid or otherwise diseased, and inspection of the attack area indicated that they hadn't been guarding a kill.

In the past 20 years, reports of human-coyote interactions which run from "I saw one in my neighbor's field" to "That rangy bastard killed Snowball" have increased exponentially: up fourfold in Texas, for example, and 16 times in California. That's not surprising: There are more people and more coyotes out there than ever before. Highly adaptable creatures, coyotes make themselves comfortable whether hunting, resting, or observing in farm fields, woodlots, and suburban backyards.

"The coyote is an experimenter," Quann says. "It will try things, and if it succeeds it will learn that behavior and pass it on." Unfortunately, many coyotes have learned to link people with food: sometimes garbage, sometimes kibble intended for pets. Though Cape Breton forbids feeding wildlife, visitors do it all the same. In the days following the Mitchell attack, Quann says, "we went to extensive lengths to curtail that learning." He has since killed four additional animals, including one that, rangers determined, was also involved in the attack. These coyotes, he says, were "possible pack mates of the first two."

Quann uses the word pack warily, preferring the wonkier "cohesive family social group." That's because pack is associated with wolves, and wolves, as we know, can bring out the worst in people. But, yes, Quann says with a reluctant sigh, "it's pretty well accepted these coyotes are wolf hybrids."

This is, to some, unsettling news. It's only within the past three years as monitoring technology has improved and the price of genetic analysis (of scat, hair, and hide from museum specimens) has dropped that scientists have proved definitively that wolves and coyotes have interbred. Now, with the attack on Mitchell, many are left wondering whether the resulting combination of traits, both behavioral and physiological, could be a recipe for future attacks on lone hikers.

The coyote that occurs in the northeastern United States and eastern Canada has been an enigma to scientists since it first appeared about a century ago. Its story began when western coyotes (Canis latrans) migrated into Canada probably through the area around Sarnia, Ontario, where wolves were absent and land had been cleared. A group that headed east through southwestern Ontario soon crossed paths with remnant populations of eastern wolves (Canis lycaon). Out west, gray wolves (Canis lupus) don't breed with coyotes; they're a distinct species. But those were hard times for Canis lycaon, and eastern wolves and western coyotes could, and did, inter­breed. The mingling of genes gave the resulting hybrids exceptional behavioral plasticity, allowing them to rapidly expand into territory where the top predators mountain lions and wolves had long been wiped out and to assume, in some places, the wolves' biological niche.

By 1940 the hybrid coyotes had crossed over the St. Lawrence River into New York State. But these weren't exactly the trickster coyotes of Native American lore: Eastern coyotes have bigger jaws than their western counterparts, are heavier and less man-shy than wolves, hunt in packs (unlike western coyotes), and commonly take down prey as big as white-tailed deer. By the 1950s they were as far south and east as Cape Cod. Today, tens of thousands of eastern coyotes roam the Northeast, while small numbers of eastern wolves make occasional forays into northern Maine. Meanwhile, western coyotes continue to migrate, via more southerly routes, into the mid-Atlantic states.

Biologists call this mixing and mingling "Canis soup," a testament to the mutability of a tremendously successful lineage. Says Roland Kays, curator of mammals at the New York State Museum, "The eastern coyote is, in the grand scheme of things, a new character on the landscape."

AS WORD OF MITCHELL's death spread, the anti-wolf crowd renewed its calls for trapping campaigns, the right to bear firearms in Canada's national parks, and a return of bounties on coyote pelts. Some deer hunters, many of whom consider coyotes their competitors, called for culling in the park. (New York and some of the New England states have limited coyote-hunting seasons, while many other states allow coyotes to be killed year-round.) But just how dangerous were these coyotes?

In most places, no one knew. Enter Robin Holevinski, a doctoral candidate at the State University of New York College of Environmental Science and Forestry, in Syracuse. Soft-spoken, with chestnut hair and blue eyes that seem more Disney princess than coyote trapper, Holevinski has been capturing coyotes in Steuben and Otsego counties for two years, collaring them with GPS units and transmitters. "We're trying to estimate coyote population and figure out how many deer they actually take," Holevinski says. "We're also trying to see whether coyote and deer density are related."

On a sunny day in early December, Holevinski and her undergraduate assistant, Jennifer Kurilovitch, parked their truck on a dirt road alongside a farm outside the town of Worcester. Kurilovitch raised an antenna overhead and slowly rotated, listening for the telltale beeps of M31, a male collared in April. Next, Holevinski attempted to sync her GPS unit to M31's. But the two computers failed to connect. "He could be behind a rock, in a den, or curled up on that hillside with his paw blocking the collar," Holevinski said, pointing to a brushy rise.

For the next eight hours, Holevinski calmly drove, stopped, listened, and triangulated four coyotes' positions, using her compass and the beeps. Now and then she'd shoulder a backpack and dive into the woods, scouring areas that had seen heavy coyote use for den sites, kills, and scat, which she could analyze back in the lab to identify individual animals.

Holevinski routinely comes upon coyote-killed deer, turkey, hare, and woodchucks. But on this day she came up empty. With the sun low in the sky, she tromped around a final hilltop, where bleached fragments of cornstalks tantalizingly resembled deer bones. "This is so frustrating," she said. Then, to the elusive M31, "Why did you spend 80 minutes in this one place?"

Otsego County, with its farms, scrub brush, and miles of second-growth forest, is textbook habitat for coyotes. And here, as in many other places, their populations are on the rise. "It's difficult to say why," Holevin­ski says. "It may be more about prey than habitat, but there's certainly more of both." Studies show that abundant supplies of food result in bigger coyote litters. And in response to hunting and trapping, females decrease their age of first breeding another brick in the species's wall of indomitability.

STILL, IT MAY BE the recent changes in coyote behavior, more than their numbers, that's causing the most consternation. Between 1960 and 2007, there were 142 reported coyote attacks on people in the U.S. and Canada. (Compare that to 4.5 million domestic dog bites.) The vast majority occurred within the past two decades in heavily populated areas of California: a ten-year-old bitten on the head while sleeping on a porch; a stargazer bitten on his foot; a woman hiker nipped on the buttocks. In the region occupied by eastern coyotes, there have been at least ten attacks in the past several years. Among the victims was an elderly man walking in the woods of central Massachusetts; a woman at a rest-stop McDonald's in Connecticut; a country-club security guard on Cape Cod who interrupted a coyote foraging for garbage; and a three-year-old playing on his swing set, also on Cape Cod.

Robert M. Timm, a wildlife specialist at the University of California at Hopland, has studied how good coyotes go bad. First, he says, they appear in yards and streets at night, possibly attracted by pet food, compost piles, fruit-bearing plants, and landscaping that harbors rodents and rabbits. Next they start killing unleashed pets and facing off against leashed dogs, then chasing joggers and cyclists. As habituation progresses, coyotes appear in children's play areas at midday. Finally, they attack adults.

The number of attacks on humans by both western and eastern coyotes will, experts believe, continue to rise. According to Timm, "the pattern seems to be that when canids of various species" whether wolf, coyote, dingo, or wild dog "move into close proximity to humans, or vice versa, and then [people] either ignore them or in some cases intentionally feed them, a few of the canids will become aggressive to the point of attacking." Eastern coyotes may be more dangerous than their western cousins, Timm says, "simply because of their size and physical capabilities." (If a coyote does attack, don't act like prey. Yell and throw things. The point is to reinstill avoidance behavior.)

Both wolves and coyotes learn about people's routines by sitting and watching them attentively. Nowhere are those routines more regular than on the trails of parks. "You've got lots of people walking in a confined area," Derek Quann says. "Coyotes realize they're not getting off the path. They may think they can get close because people haven't scared them away or shot at them."

Quann investigates coyote "interactions" year-round. "We go to the area to see if the behavior is repeated," he says. But if the aggression continues, the animal will be killed. "We want the public to understand it's not to make the guilty party pay but to stop the cycle of learning. If a coyote passes on that knowledge, it's more dangerous."

Taylor Mitchell's death forces us to confront how much wildness we're willing to tolerate and where to draw the line between natural and unnatural. We like to hear coyotes at night, but we're horrified when they maul our cats. Whether coyotes "belong" in the East or not is at this point irrelevant. The animals migrated here on their own, and they're almost impossible to eradicate. Furthermore, they're an animal we've helped to create by opening an ecological niche through the extirpation of wolves and by expanding coyote habitat when we abandon farms to brush and add wildlife corridors in urban areas.

In a statement following Mitchell's death, the singer's mother wrote, "We take a calculated risk when spending time in nature's fold it's wildlife's terrain. When the decision had been made to kill the pack of coyotes, I clearly heard Taylor's voice say: 'Please don't. This is their space.' She wouldn't have wanted their demise, especially as a result of her own."

It may be small comfort to Mitchell's family, but new coyotes will almost certainly move into the old pack's spot.