Home Invasion

It is midnight in your downtown or suburban backyard and all is quiet, or so you think. But while you sleep, there is a whole industrious nocturnal world happening under the light of the moon.

Raccoons, one of the most prevalent night prowlers, emerge as the sun sets and stay up most of the night gorging on garden delights, tearing up lawns for delicacies such as grubs, ripping apart roof shingles to gain entry to a warm attic or pulling apart flimsy boards to crawl under your deck to have babies. In other words, there’s a party happening out there and you weren’t invited. While there won’t be empty beer bottles or cigarette butts to clean up in the morning, there may be a few bites out of your cucumbers or a curbside mess on garbage day, and little footprints from multiple partygoers. Raccoons see your backyard as their land of opportunity.

From a city raccoon’s perspective, humans have kindly provided an easy means of food, shelter, water (swimming pools are their watering holes) and even a freeway system – they use the tops of fences as their personal highway to transverse the neighbourhood, says York psychology Professor Suzanne MacDonald, who studies animal behaviour.

“In a three-square block area – their usual territory size in the city – they will have about 10 den sites each and there may be about 20 raccoons,” she says. “So there will always be tons of raccoons in your backyard, you just don’t know they’re there. People think, ‘OK, I’ll just block off the hole in my roof and never see them again.’ No. They’ll just saunter off somewhere else in your yard or go to your neighbour’s.”

And if there’s one thing raccoons are good at it’s adapting to new environments. “They actually thrive next to humans, while most other species don’t.” MacDonald studies their habits, behaviours and population density – pockets of Toronto may be overrun – and her work will likely help with the city’s policy and management decisions regarding these nocturnal marauders.
MacDonald recently played a role in designing Toronto’s new raccoon-deterring green bins. Raccoons don’t have opposable thumbs; their long fingers are all in a row and the new bins are meant to foil them. At the moment, it’s working. The problem is the more puzzles we give them, the smarter they get, says MacDonald. She knows this first-hand as she constantly gives them new challenges as part of her research, such as different designs of garbage cans, to see if they can solve them.

In an effort to figure out what raccoons were up to all night, MacDonald asked her neighbours if she could install ­cameras in their backyards. “Many people said, ‘Sure, you can put your camera in my backyard but you won’t see anything. We never see raccoons,’ ” she says. “Turning on my cameras up was an eye-opener.” She uses motion-capture infrared cameras that work at night. “I can actually see what’s going on in the backyards and it’s wild. There are so many of them in all the backyards. It’s like this little secret world.”

She also put GPS collars on them to track their movements. The results were surprising. “City raccoons stay in the same general three-block area, and they don’t cross big roads. They live and they die in the same small area. As a psychologist, that really interests me,” she says. “An animal that has to figure out how to get all of its resources and find a mate and have babies, and do all that in a very small territory that is overlapped by many other raccoons and is in our backyards, that’s quite a challenge.”

MacDonald then started looking beyond the urban backyard, setting up her cameras in various places – from Georgian Bay to near Ottawa. Altogether, she amassed some 800 hours of video of ­raccoons carrying on their nightly ­business. “All this work happens at three in the morning,” she says. “Finding urban ones is not hard. You just go out in people’s backyards. But finding them in the country is quite difficult because they have large ranges.”

Her observations have led her to hypothesize that city ­raccoons are being selected to be smarter through cognitive evolution over their rural counterparts. Like city humans, urban raccoons live in denser and smaller areas than those in the country, and this has created differences.

Unlike their city relatives, country raccoons have large home ranges, some as big as 20 square kilometres. They go in and around rivers, in forests, across meadows. They don’t see many others of their species and their territories don’t overlap much. That has made the country raccoon much more solitary, says MacDonald. “They have a completely different life history than the animals that live in the city.”

The urban ones will try a multitude of ­solutions. That leaves me to suspect that, in fact, the urban ­environment is selecting for smarter raccoons

For the past several years, MacDonald has tested her hypotheses about raccoon behaviour by giving both city and country raccoons simple and complex problems. Turns out, both groups can do the simple tasks, but only the urbanites can solve the complex ones. “The latter use more strategies,” she says. “The country raccoons tend to just focus on a problem one way and then if that doesn’t work, they give up, whereas the urban ones will try a multitude of solutions. That leaves me to suspect that, in fact, the urban environment is selecting for smarter raccoons.”

She watched one female try to get into a garbage can for over six hours. “In the country they wouldn’t have six hours to spend. They’d have to go find food elsewhere,” says ­MacDonald. “The raccoon went away, she came back, she went away over the course of six hours before she got in, but she got in. That’s how they get in so successfully, because they don’t give up until they get in.”

Because they’re omnivores, raccoons can eat pretty much anything. That’s why garbage is so attractive to them. Once they’ve cracked the garbage pail puzzle, it’s an all-you-can-eat buffet of leftovers in the city. “It’s not that there isn’t food in the country, but it’s more spread out,” she says. “Our cities have resources clumped together, especially on garbage night, and there are a lot of resources in people’s backyards. They have gardens, they put food out for the cats, there are water sources. [Raccoons] will eat insects, eggs, whatever they can find. The city is food abundant and that’s why raccoons can spend six hours breaking into a garbage can. They’re quite fat in the city; they’re not that fat in the country. You’re not svelte when you’re eating takeout all day.”

MacDonald has, however, found a few things raccoons don’t like – onions and hot peppers are at the top of the list. She tests them in her own backyard, so they know where to go for a slightly burned tray of cookies or leftover fried chicken. She doesn’t recommend feeding them, though, and only does it herself for research purposes. But she notices all the onions are left behind. And if she rubs onions on her patio door, they stop placing their hands on it to peer inside. They’re also not big vegetable fans and they’re particularly not fond of tomatoes, although you wouldn’t know it. “They often take one bite out of everything,” she says. If you’re trying to deter raccoons from your backyard, things like cayenne pepper may help. Just don’t put marshmallows out. Raccoons love them and will come back looking for more.

This summer, she plans to focus on raccoon babies to see if her hunch about selection and cognitive evolution is correct. She will then compare country and city kits by giving them new problems to solve. “You’re not trying to train them; you can only give them the task once.” This will tell her if the urban kits really are smarter than their country cousins.
Taking it a step further, MacDonald believes the city and country raccoons will eventually develop into two different species. “When you have that difference in selective pressures, so that the ones in the country are dealing with a different environment and different sorts of social activities than the ones in the city, what I suspect is that there will be speciation.”
As raccoons continue to thrive in the concrete jungle, we may be unwittingly helping to create a smarter animal that will be harder to fool, but as MacDonald says, “We are going to have to figure out how to live with them as they’re not going anywhere.”  ■