JACKSON — Kelly’s resident biological research institute, Craighead Beringia South, is an outfit that keeps remote, motion-tripped cameras on the landscape simply for the sake of seeing what’s out there.
And what’s out there, increasingly, is raccoons.
“It seems like they come in waves,” Beringia South research biologist Pete Alexander said of his camera sightings. “We got this sudden burst of them in the last few weeks near the Snake River.”
The adaptable mid-size critters were once such a rarity their native status in this high mountain-enclosed valley is questionable, but now they’re appearing all over and in some places seem to be regular residents.
There’s no good paper trail of sightings of raccoon-specific research that’s been conducted in Jackson Hole, but several biologists reached for this story said that the species does not show up in the historical records. When Franz Camenzind arrived in the valley in the 1970s, a raccoon spotted near Moran was deemed so out of place people speculated that it was illegally released in Grand Teton National Park.
“Now I’ve got them around my house,” Camenzind said. “Under my deck. They’re much more common than they were 30, 40 years ago.
“I feel pretty confident in saying they weren’t here 100 years ago,” he said. “If somebody can prove me wrong, great, but I would feel pretty comfortable in saying that.”
Distribution maps showing what parts of North America raccoons occupy leave out only the most arid parts of the country, like the southwestern deserts and the Great Basin. Alexander said he’s “certain” they’re native to the general area, but just maybe not up in the highest places where winter conditions are harshest, like Jackson Hole.
When biologist Susan Patla contemplates what could explain why raccoons have proliferated, she lands on climate change. Historically, she said, raccoons that successfully dispersed into the valley were wiped out by brutally cold -30 and -40 degree temperatures during the depths of winter.
“They weren’t cold-hardy enough to survive through it,” she said.
Nowadays those frigid airflows occur with less and less frequency. In Jackson Hole, Patla said, minimum temperatures have been much more affected by climate change than the maximums. And that relative wintertime warmth has given raccoons an opportunity to gain a toehold in both this valley and the one sprawled out on the other side of the Teton Range.
“There’s been a significant range expansion,” Patla said, “and I know they’re commonplace now throughout Jackson Hole and Teton Valley.”
Jackson Hole’s status as a relatively new home for the omnivores is far from unique.
In the last half century, raccoons that were stowaways on ships and escaped as pets and from commercial fur trading operations have led to new populations in Japan, Azerbaijan and Iran. They’ve been thriving as an exotic species on several Caribbean islands since the 17th century. An introduced population in Germany in the 1930s has gradually fanned out across Europe, reaching the Netherlands in 1960, Switzerland in 1976 and Luxembourg in 1979. Raccoons now occupy all of western Europe and have “very recently” reached Spain and Italy, according to a recent Scientific Reports study, “Current and future climatic regions favorable for a globally introduced wild carnivore, the raccoon.”
That study, headed by French scientist Vivien Louppe, of Sorbonne University, compared the accuracy of two different models that predict new ground raccoons will gain across the world with a warmer climate. Both models, given raccoons’ adaptability, predicted “extensive current favorable” geographic areas for raccoons to set up shop, and “extensive new favorable” areas to the north of those in the warmer future.
As they reach new territory, raccoons may wreak some ecological havoc.
“The impact of introduced raccoons may thus be more damaging on islands where native fauna has been little exposed to predation,” Louppe wrote, “and where raccoons themselves are exposed to little predation and competition.”
Patla said that she’s not inclined to view raccoons as “exotic invaders” because of the near proximity of their historic range. Still, there will be consequences of their presence here, like increased predation of bird eggs.
“But I wouldn’t characterize it as bad or good,” Patla said. “It’s just one of the changes that we’re seeing because of the change in the climate.”
More concerning for the recently retired Wyoming Game and Fish Department biologist are species native to the valley whose presence here is threatened by climate change.
“The disappearance of the lynx could have been a real early warning sign that we missed until it was too late,” Patla said. “Really, they’re a boreal species. I think those are the species we need to keep an eye on.”