A team of researchers has found that animals, such as dwarf mongooses, may be distracted and slower to detect predators when exposed to man-made noises. Loud noises made by people and machines had a negative impact on the sensory abilities of mongooses. The details are in a paper that was just published in the journal Current Biology.
Anthropogenic noise (sounds made by human activity) is an often overlooked form of pollution. Scientists already know that this type of noise can disrupt marine mammals, making it difficult for the animals to forage and communicate. Fish exposed to this type of noise are less likely to notice predators and other threats. There hasn’t been as much research conducted with terrestrial animals.
Researchers from the University of Bristol studied dwarf mongooses (Helogale parvula) who were already used to living near human activity. The dwarf mongoose is a small carnivore that lives in a close-knit and cooperative social group. Their tiny size makes them vulnerable to larger predatory species. Dwarf mongooses normally use scent information to detect and respond to danger.
The research team played noises that replicated the sounds of road traffic. They also planted samples of feces from predatory animals in the area. The researchers then observed the mongooses’ behavior. The team found that when the traffic noises were playing, the mongooses became much less aware of their surroundings. They often failed to detect the scents of predators and showed less vigilance even after they had noticed. The mongooses also spent more time away from the safety of the home burrow. This was the first recorded case of anthropogenic noise affecting the olfactory system of animals.
The research team speculates that the noise pollution was causing the animals to become stressed, making them less likely to notice olfactory cues of predatory activity. The study points to the importance of considering anthropogenic noise to be a serious form of pollution.
Morris-Drake A, Kern JM, Radford AN. Cross-modal impacts of anthropogenic noise on information use. Current Biology (2016).