John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
A field guide to the surprising mental abilities of the most common animals living among us.
Animal researchers have no universally accepted scale of interspecies IQ. That's because each creature, from the lowly field mouse to the majestic bald eagle, has evolved a specific skill set that makes comparisons hard. Who's to say that a cat's knack for automatically mapping its environment is “smarter” than a pigeon's talent for solving math problems?
Our human opinion of what constitutes a keen intellect also makes ranking animals problematic. “When 'intelligent' behavior is language or tool use or abstract thought, humans trump every other critter out there,” says Laurie Santos, the director of Yale's Comparative Cognition Laboratory.
“But if we had, say, spatial navigation as the intelligent behavior, then New York City cabbies would have their butts kicked by rats,” she says. “And if we had flight, echolocation, nest building, etc., our species wouldn't even be in the running.”
In other words, what we see when gazing into a public park – squirrels furiously digging, rats scurrying in the underbrush, pigeons pecking at everything – is in fact an intricate ballet of counting, memorizing, threat detecting and problem solving. What are some of these animal abilities that are surprisingly advanced but mostly hidden from human notice? Have a look at this field guide to the brainy talents of some of the most common animals with which we humans come into contact, and which just might make you fear the raccoons of the future:
THE MATH WHIZ
When most city livers look at pigeons, they probably see bloated waddlesacks of breadcrumbs that do little but eat and defecate. But these birds are fiendishly advanced in terms of what they can recognize. As a New Zealand researcher recently demonstrated, they can learn to count items in groups of one, two and three. Then, without any more preparation, they could go on to determine the value of higher numbers – that nine is more than six, say, even though they haven't encountered quantities that big before. Most children don't learn to understand quantity until they're around 4.
A pigeon's ability to notice stuff extends to its own self. In 2011, Tokyo researchers interacting with caged birds noticed they not only could recognize themselves in a mirror, but also in a video recording with a delay of up to seven seconds. Compare that to 3-year-old children, who have trouble recognizing themselves in videos with a mere 2 second delay. More crazily, they have the capacity to tell apart photos of different people and also paintings executed by different artists – grouping together the works of Van Gogh versus Picasso, for instance. That's led some people to speculate they know the difference between “good” and “bad” art.
THE SAVVY INVESTOR
City squirrels have their share of pratfalls: getting so fat they get stuck in tree holes, blasting off into the air after biting a live powerline. But they're incredibly adept at building up and managing a complex network of food caches. The squirrel spends the fall burying nuts to chomp on during winter months, and the quality-control process is amazing. It cherry-picks nuts from the best trees; shakes them probably to ascertain their quality and drops inferior ones; and selects patches of earth to entomb them that are not too moist (for rotting) or too arid (where the escaping nut-smell could tip off other hungry animals).
Squirrels are misanthropic creatures, choosing to eat nuts at the end of branches while growling at any other squirrel that approaches. Their antisocial tendencies come across in their burying behavior, which can be described as “paranoid.” They do something called “scatter hoarding,” placing single nuts in single holes all over the place. That way, they don't risk another squirrel stumbling on their entire winter-food supply and wiping it out.
In what seems to be a combination of memory, smell and landmark detection, squirrels are able to find the vast majority of nuts they've buried. That's remarkable, given the extent of their hoard. Researchers at the University of California, Berkeley, who have studied the resident fox squirrels on campus for decades, found that about 70 of them maintained a network of more than 1,000 holes. Said one scientist: “Think of them as little bankers depositing money and spreading it out in different funds, and doing some management of those funds.” And all that without Excel spreadsheets!
Canis lupus familiaris
Dogs are no doubt intelligent: They've trained us, as a species, to carry their poo around in bags. But they also can be adept with language, with vocabularies on par with specially trained apes and dolphins. Evidence for their linguistic skills comes from “Rico,” a German Border Collie that learned the names of more than 200 objects and could fetch them on command. While the hound's word-trove fell short of what's needed for a good Scrabble game, researchers did note that it appeared to be “fast mapping,” or quickly associating objects with labels – a skill seen in young children learning to speak for the first time. Subsequent studies have found Border Collies that know the names for up to 1,022 toys, making these specific dogs not just the smartest, but perhaps most spoiled mutts in existence.
If you need more proof that our rear end-smelling, napkin-scarfing companions are actually quite brainy, other studies have found that they can read body language to identify who's most likely to feed them. Dogs also get potty trained at a few months, as opposed to humans' two to three years, and there's evidence they know how to count given how they gape in confusion at food bowls with treats secretly added or removed. That's at least as smart as a 5-month-old kid. (On the dumb side, dogs don't recognize their own reflections, maybe because they sense things via odor.)
THE PROBLEM CRUSHER
Ravens are scary smart, with a canniness that in certain aspects exceeds that of great apes. They seem to act not only by instinct but through methodical plans. In one study, scientists confronted ravens with a puzzle consisting of a piece of food tied to a string. One end of the string was fastened to their perch, while the end with the food went over the wall of a wire screen to dangle somewhere below them (diagram here). After pondering this setup for a couple minutes, the ravens alternately pulled the string with their beaks and stepped on it, gradually raising the food until it toppled over the wall and into their cages. The ease with which they did this made the researchers believe they were using logic, something that is thought to be lacking around most of the animal kingdom.
Ravens can also recognize individual birds that have stolen their hidden food caches, and won't hide any other food while in the company of the thief. And something that makes them seem stupid – their favorite pastime of sneaking up to larger animals and pecking the crud out of them – is more evidence of their aptitude. While it's dangerous, this behavior is teaching them about the temperament and reaction speed of potential predators, like how a pro boxer would perform some throwaway jabs to gauge the skill of an opponent.
THE MUSCLE LEARNER
With a yen for squishing into tiny spaces and chasing imaginary prey, cats are strange in many ways. One of the strangest, most extraordinary things about them is the way they learn to map their environment. While a human might glance around a room to comprehend what coffee table or TV stand they don't want to bang against, a cat makes these memories by physically interacting with the object.
Canadian researchers made this finding a couple years ago by putting meowers through a test involving a removable barrier. When the cat stepped over the barrier to get to its food, that memory was cemented in its brain – it would always lift its legs at that point, even if the barrier was taken away. But if it only saw the obstacle from afar, it would invariably trip over it when going for its treat. While researchers don't fully understand why this happens, they surmise it has something to do with the motor cortex sending signals to different parts of the brain, one that causes body movement and the other that memorizes terrain. On a side note, the average human child doesn't learn to use maps until about 5 years of age.
THE FREEDOM FIGHTER
It may come as a shock that one of the most detested pests in human history, the rat, appears to share a celebrated human attribute: altruism. Chicago researchers demonstrated this in 2011 by putting two rats in a cage, with one free to roam about and the other locked inside a small enclosure. Out of the 30 “free” rats tested, 23 head-butted or leaned against the enclosure until it opened to free their trapped kin. Their concern for the penned-up rodents lasted in a subsequent experiment when a duplicate enclosure of delicious chocolate was added to the cage. Most of the rats chose to release the prisoners before they went for the food. The animals wound up eating it together.
With their little sausage fingers and thumbs, raccoons already draw comparisons to humans. But now there's evidence they're actually exploiting human civilization to grow smarter. Researchers have known for more than a century they're very hands-on; in 1907, one psychologist showed they could undo a series of latches to escape from cages (and then do it quicker the second time around). A couple years ago, wildlife experts discovered that raccoons in Toronto had gotten even more dexterous. Using night cameras, they witnessed the creatures unlocking garbage cans that people had tried to raccoon-proof. The implications of that are disturbing, according to animal biologist Sue MacDonald:
“One of the things we are doing is providing them with bigger and bigger challenges, so you have probably seen raccoon-proof garbage and all these things to try to keep them from figuring things out.... But in fact they always do, so humans are selecting these traits in raccoons, and we’re actually shaping an über-raccoon that is going to be able to compete in an urban environment.”
The cauldron from which this super-raccoon will eventually rise is no doubt Toronto, whose legions of the beasts grow to epically large sizes and show no fear at all toward humans. Look, here's one fashionista who even made a living jacket out of them.