Science

Will Raccoons Trump Rats as the Ultimate Urban Mammal?

They’re expanding into suburban and urban landscapes, and excelling, thanks to our help.

A racoon holds on to a tree high above McPherson Square 22 February 2000 in Washington, DC.
A racoon holds on to a tree high above McPherson Square in Washington, D.C.

Joyce Naltchayan/Getty Images

Late this summer, a raccoon kept entering my mom’s house through her cat door. This particular creature was savvy, dexterous, and driven, a kind of super-raccoon combining all the strengths of its species with none of the reticence of its country brethren. This isn’t the first time a raccoon has snuck through my mom’s cat door over the past five or six years. (Once, when my mom wasn’t wearing her glasses, she thought the interloper munching from the food bowls was simply one of her cats, a big Maine coon.) But previous invaders were chastened by being chased out, and never came back.

This latest raccoon, however, had moxie. Even my broom-wielding husband, confronting it late one night, could not deter the persistent mammal. Using its tiny hands and considerable strength, it managed to break through an escalating series of barriers my mom erected. She knew of the raccoon’s triumphs because she had set up a night-vision camera to track them. Mornings, she’d send me grainy, black-and-white videos of the previous night’s break in. She escalated; after blocking the door with cardboard, she tried a bulletin board attached with Velcro and, when that proved laughably inadequate, talked ominously of going to Home Depot to pick up some cinderblocks (she ultimately decided they would be too heavy for her to move). While my mom had the bigger brain and opposable thumbs (not to mention access to technology and big box stores), the raccoon was clearly taken with the challenge. Quite against my mom’s will, she appeared to be making it more persistent and—worse—smarter.

It turns out, we all may be unwittingly participating in the mass education of raccoons, which is resulting in the creatures’ increasing domination of the human landscape. The raccoon population has enjoyed an “astonishing” surge over the past 80 years, according to zoologist Sam Zeveloff. They’re apparently at highest density in the suburbs, but they appear to be also growing in cities. The animals have adjusted remarkably well to living alongside human beings—perhaps because when they live with us, they seem to learn from us.

Suzanne MacDonald, a psychologist and biologist at York University in Toronto, has done research suggesting that city raccoons might be smarter than rural ones because they’re constantly forced to navigate human-made obstacles. She tracked urban raccoons outfitted with GPS collars and found that they avoided crossing major roads, as if they’d learned to avoid cars. She placed tough-to-open garbage cans in both the city and country, with delicious treats like cat food at the bottom, and found the urban raccoons, for the most part, could solve the puzzle, while the rural ones had no success whatsoever.

In other words, we’ve inadvertently set up perfect little city classrooms, in which the raccoons are learning how to become “perfect little urban warriors,” as MacDonald calls them.

That’s perhaps because they start with fabulous raw materials. They’ll eat anything—human trash, pet food, bird seed—and they can see at night, when garbage cans are exceedingly easy to raid. They’ll happily adapt to sleeping in various cozy nooks on your property, including under decks and in attics and chimneys, over their traditional tree hollows and burrows. They have lovely little nimble hands, which are so sensitive that they can essentially “see” by feeling objects, according to raccoon expert Stanley Gehrt. To get into small spaces, like under your garage door, they can “squish their spines down,” MacDonald says. They’re smart, and they’re curious. They can open refrigerator doors, pry apart Tupperware, unzip tent zippers, turn doorknobs (after considerable effort), and wheel toddler trucks across the floor.

“I would put their little brains up again pretty much anything,” MacDonald says. Studies from the early 1900s put raccoons near monkeys—and ahead of cats and dogs—on several measures of intelligence. (Raccoon brains are seriously overdue for study. Early comparative psychologists were fascinated by them, according to a short history of the topic, but their work devolved into academic squabbles, and there hasn’t been a lot of research into raccoon psychology since.)

All of which explains why I’ve heard so many stories about the smarts and persistence of raccoons lately: from the gardener whose crop of cantaloupes was decimated by raccoons who managed to scale a six-foot-high fence. Or the guy who told me he eventually had to set up an “elaborate Rube Goldberg mechanism of ropes, pulleys, and rakes” to kick a humongous raccoon out of his Rubbermaid garbage shed. I heard a story of homeowners who tried to discourage a raccoon from coming in their cat door by setting out smelly bars of Irish Spring soap (this didn’t work), as well as heavy quantities of human urine (which, ugh, also didn’t work). And I heard from a friend who works in the State Department about a raccoon that snuck into her building while it was under construction, and then walked across ceiling tiles until it got to her office and hung out above her desk, visible through the mesh-type ceiling panels, perhaps attracted by the scent of her sandwich.

MacDonald says she once mistakenly left her garage door open by a couple of inches and a whole bunch of raccoons got in, stepped in some open white paint, and wiped their wet feet and tails all over her deck.

“All you have to do is lose your focus for one night. They’re right on it!” she says, with the intensity of an Olympic coach. “I think that’s why I love them so much.”

In recent years, anti-raccoon sentiment has been building across North America like a brush fire, fueled by growing numbers and by the rise of what MacDonald has termed “uber-raccoons” like the one that invaded my mom’s house. Zeveloff says the North American raccoon population is estimated to have swelled 15 to 20 times between the 1930s and 1980s. Since then, it has continued to grow as more raccoons colonize not only cities and suburbs but deserts and mountainous areas, where they were once rare. The New York Times recently chronicled how the animals are invading Brooklyn, living in chimneys and staring into people’s windows from their fire escapes like hungry street urchins. There’s often an apocalyptic tone to coverage of the mammals, as if they might eventually displace us. In Toronto, which has earned the unfortunate title of “raccoon capital of the world,” a man was arrested for allegedly hitting a baby raccoon with a garden spade, and his supporters organized an “anti-raccoon rally.” When the city unveiled what are supposed to be raccoon-proof green bins, after years of problems, the mayor declared that “defeat is not an option.”

While raccoons are more likely to have rabies than many other wild animals, and also carry roundworm in their droppings, cases of fatal transmission to humans is small. More than the threat of disease, the thing we seem most flummoxed by is their gall. The animals seem not to know their proper place in the animal pecking order. At least rats know when to hide. Raccoons seem to regard humans as the rube roommate who overstocks the fridge and conscientiously cleans up after everyone else.

Of course, we don’t really like to equate ourselves with animals, so we often don’t think about where we ought to belong in the pecking order. But it’s us humans who have expanded our environment into animal territory. So far, we seem to have done so quite successfully. Raccoons are simply flipping the script by adapting instead of running away.

Besides, just what constitutes a pest depends on whom you’re asking. Native to the New World, raccoons stand for “wilderness and freedom … self-reliance and adaptability,” argued a 1963 Harper’s piece that called them more American than the bald eagle. One writer, pointing out how traits like adaptability and opportunism are shared by humans and raccoons, asks: “[I]f we reject animals for their destructive habits, at what point do we turn the gaze on ourselves?”

It’s anyone’s guess how far the uber-raccoon will go. Gehrt, a professor of wildlife ecology at Ohio State University who studies Chicago’s raccoons, points out that in some parts of the city, food is so abundant—think open dumpsters—that they may be using their brains less than their country counterparts. (Some of the raccoons Gehrt studies are so fat that they’ve developed health problems just as overweight humans sometimes do.) Perhaps their opportunism will end up dooming them—and serve as a frightening analogy for humans’ current trajectory. For her part, MacDonald is currently designing a study that will attempt to tease out whether changes in intelligence are happening within individual animals or on a grander scale.

“If we have this evolutionary arms race to keep them out [of our attics and garbage cans], and those that survive figure out how to get in, then what you’re going to see over generations is their brains are different,” she says.

One thing is clear: We are adapting to them as much as they are adapting to us. In coming weeks, we may do even more adapting, since Gehrt says late summer and early fall is the time of “maximum raccoon visibility” in many parts of the Unites States, as young kits are gaining independence and exploring new territories and raccoons all over are feasting to get ready for their semihibernation.

As for my mom, her attempts at blocking the enterprising raccoon finally worked. She put a board against the cat door and, behind that, a crate holding 44 pounds in free weights, which proved too heavy for the animal to push aside. Victory! She sent me video evidence with the subject line, “Foiled.” As a reward, the raccoon seems to have started going after the food in her garbage can. Only time will tell whether the “Animal Stopper” can she bought to thwart it will work, or whether the raccoons will have something new to teach her.