The life of urban wild animals is a fascinating world: we are talking about animals that have to reconcile their needs with a non-natural environment, and therefore often have to invent solutions and tricks to survive in situations that are unusual for them.
There are obviously those who struggle and those who have demonstrated the ability to adapt very effectively: the latest case studied is that of gray squirrels, which according to a study by the University of Exeter published in Oikos they have learned to use traffic noise to their advantage, and feel safer when surrounded by cars whizzing by and humans making noise.
The reassuring sound of traffic. The study was conducted in England, in various environments at different degrees of urbanization; the team chose American gray squirrels, an invasive species that has been creating problems for native populations of red squirrels for years, replacing them and driving them out of their habitat.
Gray squirrels also tend to be less afraid of humans, and to understand how our proximity influences their behavior, the Exeter team monitored a series of more or less urbanized areas, leaving food available and observing how the squirrels behaved when faced with this unexpected gift.
The science of leftovers. The study was actually based on leftovers: the amount of food “left behind” by the squirrels was interpreted as a signal of how comfortable the animals felt in that specific environment. Well: apparently, squirrels eat with more gusto when they are closer to a busy road, demonstrating that our presence is not a deterrent – on the contrary.
Country squirrels, city squirrels. The results are actually more complex than that, because what matters is not just the noise but its constancy. This means that busy roads, near which the traffic chaos never stops, are seen by squirrels as safe places, perhaps because they know that predators avoid crowded areas. The areas, so to speak, “noisy but only at times”, for example those where traffic is concentrated at specific times of the day or is more scattered and therefore more random, are considered by gray squirrels to be less safe.
Urbanization therefore has a complicated, but still unexpected, effect on squirrels: the more intense and constant human activity is, the safer these animals feel from predators.
According to the study’s authors, as counterintuitive as this may sound, it actually demonstrates why American gray squirrels adapt so well to urban life.
