Noise pollution can affect how wild animals respond to other sensory inputs, such as smell.
Andrew Radford and his colleagues at the University of Bristol, UK, studied the behaviour of wild dwarf mongooses (Helogale parvula; pictured) that had been habituated to the presence of human observers. The team placed faeces from either a predator or a herbivore outside the mongoose burrow. When ambient natural sounds were played, mongooses were quick to inspect both types of faeces. In response to predator faeces, the animals showed increased vigilance and stayed close to the burrow. By contrast, when road noise was played, mongooses were slower to approach and showed similar responses to both predator and herbivore faeces.
Noise pollution may distract the mongooses and increase stress, impairing the creatures' natural anti-predator behaviour, the authors say.