When Claude Thériault took out the recycling one day in March, he was surprised to find an unexpected visitor hanging out on his doorstep.
“When I opened the door, the opossum was right there on the deck,” said Thériault, who lives in a suburban area of Saint-Jean-sur-Richelieu, Que.
“I almost stepped on him!”
Didelphis virginiana, the marsupial commonly known as the North American or Virginia opossum — or simply, a possum — lives mostly in the United States, Mexico and Central America. Its northernmost habitat stretches into Quebec’s Eastern Townships, southern Ontario and the Fraser Valley in British Columbia.
But in recent years, opossums have frequently been spotted in the Montérégie region, on the South Shore of Montreal.
Anecdotally, residents of municipalities such as Otterburn Park, Saint-Jean-sur-Richelieu, Varennes and the Saint-Hubert sector of Longueuil, as well as in the Kanien’kehá:ka (Mohawk) community of Kahnawake have all reported seeing them.
While the first opossum sightings in Quebec date back to 1976, the population has been expanding since 2000, according to the province’s Ministry of Forests, Wildlife and Parks.
The animal is considered “well-established” in the Montérégie, albeit in “low density,” and they’ve even been seen around Mont-Saint-Hilaire, according to the ministry.
“People are often a bit scared when they see them for the first time because they’re funny-looking,” said Carole Lacasse, director of client services at Proanima, an animal shelter with contracts with many South Shore municipalities.
She said the shelter often gets calls about wild animals in people’s yards, including opossums.
“They look like a big rat. But they’re totally different than the rat as an animal,” she said. “And they have moustaches … they’re actually ugly and cute at the same time.”
Lacasse says opossums aren’t often seen near the shores of the St. Lawrence River. “But as you go south, we start to see them,” she said.
Habitat range expanding
Some opossums have even been seen north of the St. Lawrence river, as far as Trois-Rivières in 2017, Boisbriand in 2020 and in Barkmere, in the Laurentians last year.
The ministry keeps track of reports of dead or injured animals but says, since it’s not mandatory for citizens to report live opossum sightings, the government has only a partial portrait of the evolution of the population.
Thériault said it’s only in the past couple of years that he has started noticing the animals in his neighbourhood — sometimes, unfortunately, as road kill.
The opossum on his porch had what appeared to be scars from frostbite on its ears and tail.
“The two ears were pretty dark and the same thing at the end of his tail and one of the ears has a little bit of blood,” he said.
The injuries from the cold are perhaps not surprising, as opossums do not hibernate, said Jean-Philippe Lessard, associate professor in the department of biology at Concordia University.
Warmer temperatures, urban development lure opossums north
While Lessard’s research isn’t directly related to opossums, his lab studies how biodiversity and species distribution are affected by human activities.
“Southern Quebec was probably too cold or the winters were probably too long for things like possums, wild turkeys and turkey vultures until recently,” he said.
The opossum is just the latest in a long line of species whose habitats are shifting toward the poles, as temperatures climb, according to Colin Garroway, associate professor in biological sciences at the University of Manitoba.
“Southern species are moving north into northern species’ ranges. That’s messing with the biology in all sorts of interesting ways,” he said.
For example, Garroway and his colleagues have studied the incursions of killer whales farther into Arctic waters and the interbreeding of once distinct northern and southern species of flying squirrels.
He points out that other species that we might think of as native to Quebec, such as white-tailed deer and coyotes, also moved northward in the early 1900s and 1940s respectively.
Those species, like opossums, are influenced by urbanization, as they look to human-created food sources, like garbage, or in the case of deer, new buds that grow after tree cutting.
Both Garroway and Lessard say it’s not clear how the opossum might affect Quebec’s ecosystems.
“They’re weird, right? They come from a totally different evolutionary branch than our mammals here because they’re marsupials,” Lessard said.
“There might be things about their biology that makes them different enough from our native species of mammals that they might not have a very negative impact.”
Still, opossums are yet another signal of the effects of rapid climate warming and urbanization, Garroway said.
“I think [opossums] are just one more indicator that we’re changing things in substantial ways,” he said.
A backyard fixture, but not a tick fixer
While opossums are a relatively new arrival to Quebec backyards, Lacasse said the advice for dealing with them is generally the same as for other wild animals — leave them alone and don’t feed them.
“If you’re leaving food for a cat or anything, don’t leave it at night. Remove all the food,” she said.
Opossums are likely to seek shelter under a porch, but usually do not destroy property or act aggressively with humans, even going so far as to play dead — or possum — to avoid an attack.
But, like any wild animal, it could bite if it feels threatened and can’t escape, Lacasse said.
“If ever we run into one and they’re scared … just let them be and go away,” she said.
While popular knowledge suggests that opossums are a weapon against Lyme disease due to a voracious appetite for ticks, this is not the case, according to a publication from Quebec’s Wildlife Ministry.
Opossums do “meticulously groom their fur” and eat the ticks they find, the ministry says.
But the idea that they help reduce tick populations is an “incorrect interpretation” of a 2009 study of opossums in captivity that was not replicated in the wild.
The ministry adds that “protecting an opossum and keeping it near the home in the hopes that it will protect you from Lyme disease is not only inefficient but also harmful to the animal.”