A steady hum of traffic may make urban grey squirrels feel more secure than silence at least from predators. A new University of Exeter study has found that predictable, consistent road noise lowers the caution levels of squirrels living near busy streets, subtly reshaping how they forage, feed, and survive in human-dominated landscapes.

Noise and the “Landscape of Fear”

In nature, predators hunt by stealth. Sudden sounds a hawk’s wingbeat, a rustling leaf can be cues that trigger flight. But when background noise is constant, those warning signals blur. The study, led by Dr. Kristin Thompson, shows that squirrels living close to main roads in the UK treat such steady noise as a sign of safety, not danger. Ecologists call this behavioral map of vigilance and avoidance the “landscape of fear.” It defines where and how animals feed, rest, and move. In this case, the low, steady drone of traffic altered that landscape, making roadside foraging spots feel safer than quieter patches further away.

“This ability to navigate complex risks is one reason grey squirrels thrive in cities,” said Dr. Thompson. “But it also shows how deeply human noise reshapes wildlife behavior.”

Testing Fear with Food

To measure risk perception, the team used a classic behavioral test known as “giving-up density.” In simple terms, the more food an animal leaves behind in a foraging tray, the riskier that spot feels. Researchers placed paired trays one under cover, one in the open across urban and suburban sites. They found that near loud, predictable road noise, squirrels were more likely to finish their meals, showing reduced fear. In contrast, areas with variable or intermittent noise triggered caution: squirrels left more food uneaten, suggesting they were on higher alert. The scientists also logged sound levels, vegetation cover, and distance from roads to control for other factors, building a detailed model of how noise predictability shapes urban wildlife behavior.

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Predictable Sound, Unpredictable Consequences

While steady noise may dampen startle responses, it also brings unintended risks. Squirrels that feed confidently near roads are more exposed to vehicle collisions, while clustering close to curbs could alter seed dispersal patterns and urban plant diversity. The researchers caution that the finding doesn’t mean traffic noise benefits wildlife rather, it changes how animals allocate attention and interpret danger. Similar effects have been observed in birds, where long-term noise exposure correlates with stress hormone changes and reduced reproductive success.

“Human soundscapes can cut both ways,” noted Dr. Sasha Dall, co-author of the study. “Steady noise may dull fear, but it can also increase the odds of fatal mistakes.”

Urban Design Implications

The study adds to a growing body of evidence that sound not just space or light matters for wildlife in cities. Urban planners and park managers could use these insights to design more wildlife-friendly green corridors. Consistent maintenance schedules and predictable noise periods, such as daytime roadworks or leaf-blower use, may help reduce startle effects. Likewise, quiet windows at dawn or dusk could allow wildlife to forage safely during peak activity times. Planting shrubs near roads, curving pedestrian paths, or installing noise-dampening vegetation can gently guide animals away from traffic without barriers or signage.

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Why It Matters?

Grey squirrels, though often seen as urban regulars, play important roles in seed dispersal and ecosystem dynamics even as they compete with native red squirrels in parts of Britain. Understanding how they interpret noise can help shape safer, more balanced urban ecosystems. The researchers stress that the work measured perceived risk, not actual predation events. Still, it offers a rare glimpse into how behavioral adaptation can emerge from subtle shifts in human activity. As cities grow louder and wildlife adapts, studies like this reveal an uncomfortable truth: sometimes, the sounds that make us restless are the same ones that make other species feel at home until they get too close

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