Columbus — Wildlife researchers have completed a study that may settle the question of why, in October 2009, a group of coyotes launched an unprovoked fatal attack on a young woman who was hiking in a Canadian park, the online news site Newswise reported.
By analyzing coyote diets and their movement in Cape Breton Highlands National Park, where the attack occurred on a popular trail, the researchers concluded that the coyotes were forced to rely on moose instead of smaller mammals for the bulk of their diet – and as a result of adapting to that unusually large food source, perceived a lone hiker as potential prey.
According to Newswise, the findings essentially ruled out the possibility that over-exposure to people or attraction to human food could have been a factor in the attack – instead, heavy snowfall, high winds, and extreme temperatures created conditions inhospitable to the small mammals that would normally make up most of the coyotes’ diet.
“The lines of evidence suggest that this was a resource-poor area with really extreme environments that forced these very adaptable animals to expand their behavior,” said lead author Stan Gehrt, a wildlife ecologist at Ohio State University.
“We’re describing these animals expanding their niche to basically rely on moose.
And we’re also taking a step forward and saying it’s not just scavenging that they were doing, but they were actually killing moose when they could. It’s hard for them to do that, but because they had very little if anything else to eat, that was their prey,” he said. “And that leads to conflicts with people that you wouldn’t normally see.”
The research is published in the Journal of Applied Ecology.
Newswise reports that the death of 19-year-old folk singer Taylor Mitchell is the only fatality resulting from a coyote attack on a human adult ever documented in North America.
Gehrt, who leads the Urban Coyote Research Project that has monitored coyotes living in Chicago since 2000, was consulted by media for his expertise after the attack. In urban areas like Chicago, where thousands of coyotes live among millions of people, injuries from coyotehuman encounters are very rare.
“We had been telling communities and cities that the relative risk that coyotes pose is pretty low, and even when you do have a conflict where a person is bitten, it’s pretty minor,” said Gehrt, a professor in Ohio State’s School of Environment and Natural Resources. “The fatality was tragic, and completely off the charts. I was shocked by it – just absolutely shocked.
“A lot of people began wondering if we were at the front edge of a new trend, and if coyotes were changing their behavior. And we didn’t have good answers.”
Gehrt expanded an initial investigation of the fatal attack into a detailed field study. Between 2011 and 2013, he and colleagues captured 23 adult and juvenile coyotes living in the Cape Breton park and fitted them with devices to document their movement.
To obtain dietary information, the team also snipped whiskers from the live-captured coyotes and from the bodies of coyotes implicated in the fatal attack and in other human-coyote incidents, Newswise reported. For comparison, the researchers collected fur from potential prey – southern red-backed voles, shrews, snowshoe hare, white-tailed deer and moose – and hair from local barbershops that served as a proxy for human food.
Seth Newsome, a professor of biology at the University of New Mexico and corresponding author of the study, analyzed stable isotopes of carbon and nitrogen in these whisker and hair samples to determine what the coyotes had been eating in the months before they were captured or lethally removed from the population, Newswise reported.
The analysis showed that, on average, moose constituted between half and two-thirds of the animals’ diets.
“This dietary evidence was the critical piece to it,” Gehrt said. “Their diets changed because they’re taking advantage of whatever different food items are available at the time …”