Evolving for city life

I’ve been thinking about the landscape of fear quite a bit lately. It’s like a map of risk—you fear being killed, so you map out those hotspots in your head so you know to avoid them. Like when you were a kid and tried to avoid that bully that always stood on the corner by the willow tree. You didn’t want to get a noogie, or give up your lunch money, so you took the long way to school instead.

In the wild, this landscape of fear dictates that prey species tries to avoid places their predators will be. That could be by trying to avoid them in time, or where they happen to be in space. So deer will try to avoid wolves for example. When you feel fearful, you’re going to spend more of your time in safe areas (like huddled up on the sofa watching Netflix). So a deer may stay in a safe area, forage more there, which can in turn affect landscape change—not just through browsing, but also from a localized concentration of seed dispersal (that’s right, lots of poop piling up 💩). But what happens in areas where we’ve gotten rid of the predators?

We humans become the only scary predator left. In the UK, we killed off wolves and bears hundreds of years ago, so it makes sense that those predators aren’t scary anymore to the other wildlife living there. Badgers in the UK showed clear response to avoiding humans, but weren’t very fearful of their natural, but now extinct predators, bears and wolves. Like how vaccination has led many people to forget the horrors that many diseases can bring, which led to declines in vaccination rates, and we’re now seeing a resurgence in those preventable diseases. Badgers, vaccines. Tomayto, tomahto.

Within cities, we humans eradicate predators. We don’t want predators to pose a risk to ourselves, so any wildlife that can find a way to tolerate humans does well to hang out in the predator-free environment we’ve created. I guess it’s better to only have to be fearful of the humans, rather than the bears, wolves, cougars as well as the humans. Those urban wildlife that live amongst us may also become acclimatized to us and become less fearful. So you have deer bedding down in your yard for the night, or have raccoons that go through your garbage like it’s a buffet. But interestingly, some urban wildlife are also becoming more clever, developing resistance to pests, changing bird song, and may be evolving for new niches.

By the year 2050, the United Nations estimates that nearly 70% of the world’s human population will live in cities. I’m curious to see if urban wildlife will continue to urbanize with us. And if so, what will that look like?