This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
"Maybe I'm not cut out for city life
the smell of exhaust, the smell of strife"
- Lou Reed
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Not everyone adjusts well to living in a city. Having spent a few days in Manhattan earlier this year, I can say quite unequivocally that I'm one of those people. The size of the buildings, the speed and energy with which people move - it's fascinating, beautiful, and would overwhelm me in a matter of weeks. I'm impressed by anyone who fits in to that kind of intense culture, but I'm even more impressed by the animals that do.
Think about it - we, as human beings, have all this intellect and adaptability at our disposal. We built those cities - it seems only natural that we master them. But we are not the only creatures which have taken to our metropolitan masterpieces, and we're not the only ones who flourish in them. Creatures you would never expect have moved in to our neighborhoods and made even our coldest cities welcome habitat. To do so, they have overcome the overpowering sights, sounds and smells that form the charm - and repulsion - of big cities.
There is more to your everyday park pigeon than meets the eye. Birds are common in all cities, from the frozen alleys of Moscow to the sizzling streets of Miami. What makes birds such good city dwellers? Urban birds tend to be smart and adaptable, much like the people they fly over. They're omnivores in the truest sense, eating a wide variety of foods from restaurant scraps to stale bread tossed by park-goers. Moreover they take advantage of the benefits a city has to offer, including warm places to nest in the winter.
While we might be aware of the pigeons or sparrows, we often fail to see the complexity and diversity that characterizes the urban bird community. There are over 70 different bird species in residence in Tokyo. There are whole websites dedicated to birding in New York City. Did you know that New York and Berlin have the highest concentrations of peregrine falcons in the world? Or that one of the most successful urban birds in the 21st century is the parakeet?
Of course, birds aren't the only group of animals that has taken well to cities. Perhaps some of the most impressive examples of city dwellers are mammals. There's no question that rats and mice have been making our cities home for almost as long as we have. These vermin serve not only as examples, but as a tempting food source. As it turns out, the abundance of rodents has attracted other mammals to test their hand at city life.
In Illinois, red foxes have decided that humans make better neighbors than coyotes. The sly carnivores have been slowly moving into suburbs and cities ever since coyotes took back the fields where the foxes normally roam. Ecologists which study these urban foxes have determined that they live longer, healthier lives than their rural counterparts, with a diet that is almost 50% rodent. In the country, coyotes kill almost half of the young foxes and a quarter of the adults, making the cities seem like a safe and welcoming place for a fox to raise her young despite the risks. It's not just cities in Illinois that are getting these new furry inhabitants - foxes have become common in cities around the world, including London and Zurich.
While the foxes have moved into cities more recently, their cousins, dogs, have made cities their homes for much longer. In Moscow, the stray dog population has become a cultural phenomenon. There are around 35,000 stray dogs in Russia's capital city. They have been living with the people there for at least the past 200 years, and have evolved specialized behaviors which help them survive in their urban habitat. Though there are many different strategies employed by these urban canines, perhaps the most well known and the most impressive are the metro dogs, which have taken to using the subway.
The metro dogs don't just haphazardly transit the underground system; they have complex territories with specific stops and routes. Becoming a savvy subway rider has changed how the dogs look and behave. Gone are the spots and floppy ears we associate with domesticated pups, for these are truly feral dogs. Yet instead of pack hierarchies led by the strongest brute, the metro dogs are led by the smartest. Because of the complex nature of their territories, they rely on brains, not brawn, for survival.
Cities bring out the ingenuity in animals large and small. Squirrels have been documented waiting for crosswalks to turn green, even in the absence of people walking. A peculiar cat used to ride the bus every morning. When animals are forced to deal with the chaos of our city life, they find a way to adapt, and then some.
All of this begs the question: what evolutionary impact are our cities having on animals long term? Selection for ingenuity could dramatically change the animals we know today. Riding subways might be a parlor trick compared to what the urban wildlife of the future will be capable of. One thing is for certain - the intelligence and adaptability of our streetwise species will never cease to amaze me.