An analysis of nearly 20,000 photographs taken by volunteers across the United States revealed a noticeable difference between urban and rural raccoons.
Urban inhabitants have, on average, 3.56% shorter snouts — a small but statistically significant change. This trend persists across different climatic zones, indicating a general adaptation to the urban environment.
Scientists link this to the domestication syndrome — a set of traits (shortened snout, smaller teeth, spotted coat) that arise in species that become calmer and more tolerant of humans. In cities, it is not the most aggressive animals that succeed, but rather the more balanced ones that better find food in trash and avoid conflicts with people. Thus, available food waste becomes a powerful factor in natural selection.
Such changes are part of a global trend. Similar traits (shortened snouts, reduced sexual dimorphism) are observed in urban foxes in London and mice in Switzerland.
The study demonstrates how human activity unconsciously shapes the appearance of wildlife, potentially bringing some species closer to domestication. Scientists note that more rational waste management could slow down this process.
