Bothered by Noise? Try Being a Bat

Human noise is a rising global pollutant. Urbanization, road networks, and energy extraction infrastructure are all widespread and expanding sources of acoustic waste. In the contiguous 48 states today, to take just one illustration, nearly 4 million miles of road cover the country; as a result, no area is more than 21 miles from a potential vehicle rumbling down one.

All this noise doesn’t go unnoticed by our non-human brethren. Some and , for example, have (perhaps grudgingly) resorted to adjusting the pitch of their calls to avoid overlap with human-generated sounds; males of several bird species have found that they need to sing , songs in noisy urban environments, lest their mating calls be muffled; and still others at which they sing to avoid the noisiest times of day. As a pair of researchers from the Netherlands wrote, back in 2006, “We found consistently higher minimum frequencies in ten out of ten city-forest comparisons from London to Prague and from Amsterdam to Paris.” Thanks to this flexibility, animals have been able to cope, to some degree, with human ruckuses.