Every year, thousands of deer are killed on roads and highways. Those collisions can lead to costly insurance claims, injuries, and deaths which made scientists wonder what would happen to deer, and to us, if an elusive carnivore came back to the northeast.
In a WNPR interview, Laura Prugh, a wildlife ecologist at the University of Washington said, that to humans, deer are statistically the most dangerous wild mammal in North America.
“Everyone’s been in a car wreck with a deer out East or knows someone who has,” said Prugh. Each year about 200 people die in 1.2 million crashes with deer across the U.S.
Prugh estimates those car accidents are enough to cost Americans more than $1.5 billion in damages, which made her curious “to explore what would happen if cougars did return to the Eastern U.S.”
The U.S. Fish and Wildlife Service declared Eastern cougars extinct. Today, the only populations that can live and breed on their own are Western cougars and Florida panthers. But those cats appear to be wandering farther from home.
In 2011, a cougar was hit by a car on a highway in Milford, Connecticut, and genetic testing revealed that cougar came all the way from South Dakota. Prugh and her colleagues believe that and other sightings in the Midwestern states raise the future possibility of a permanent population of Eastern cougars, which could impact deer populations.
To find out how, Prugh took lots of deer data, looking at birth rates, population density charts, and car impacts. Writing in the journal Conservation Letters, her team paired that up with cougar predation information from the Western U.S. and estimated that, over a 30-year period, cougars would reduce Eastern deer densities by 22 percent.
“Because they reduce deer density by 22 percent, then we projected that they would also decrease deer-vehicle collision rates by 22 percent,” Prugh said. Her team believes bringing cougars back to the region could actually save lives.
“As [an] idea it’s great,” said Morty Ortega, a wildlife ecologist at UConn. “Will it really work? It’s very difficult for me to see it here in Connecticut,” Ortega said. “I could probably see it a little bit more in Maine, for example.”
Places where there are more continuous, and remote, forest landscapes. Ortega said Connecticut could potentially support mountain lions, but forest fragmentation means only a handful could live here at any one time and they’d have to adapt.
“This lion would have to learn how to cross highways; how to move around and about,” Ortega said. “And they will be moving within the backyards of a lot people.”
Prugh acknowledged her opposition: “Basically, a cougar is a 100-pound killing machine that has millions of years of evolutionary history as a specialized predator; an obligate carnivore,” she said. “They do specialize on deer, but they will, occasionally, attack people or pets.”
Prugh said the fear of a cougar attack outpaces the reality, but in the U.S. and Canada, over more than a century, cougars have killed 21 people.
Bill Hyatt, a bureau chief at the state Department of Energy and Environmental Protection, said even if mountain lions did come back to Connecticut, they couldn’t persist in the places where deer controls are most needed, like Fairfield County.
“Our overabundant deer populations tend to be in areas that are fragmented and highly residential and those are areas that would be least likely to be able to effectively establish a large predator,” he said.
Prugh said the aim of her team’s paper isn’t to necessarily inspire major cougar reintroduction efforts, “but if they do arrive of their own dispersal from the Midwest,” she said, “cougars would be more likely to succeed if the residents in the East are a little more welcoming of having them around.”