Understanding the impact of human disturbance on wildlife populations is of social importance, as anthropogenic noise is known to impact a range of taxa, including mammals, birds, fish and invertebrates. Although animals are known to use acoustic and other behavioral mechanisms to compensate for increasing noise on an individual level, our understanding of the impact of noise on cooperative social animals remains limited.

In a new study, a team of researchers led by the University of Bristol examined the effect of sound on coordination between two bottlenose dolphins performing a cooperative task. They found that the cooperating dolphins are less successful in the presence of human-generated sound.

Two trained and highly driven bottlenose dolphins at the Dolphin Research Center in Florida, USA, had suction cup tags attached by scientists collaborating with colleagues around the world. This allowed scientists to record the dolphins’ vocalizations as they cooperated on a task. The dolphins had to work together to simultaneously press their respective underwater buttons while being exposed to increasingly loud noise levels during the task.

Lead author Pernille Sørensen from Bristol’s School of Biological Sciences said: “We have known for years that animals can try to compensate for the increased noise in their environment by adjusting their vocal behaviour. Our work shows that these adaptations are not necessarily sufficient to overcome the negative effects of noise on communication between cooperating animals.”

Dr. Stephanie King, lead author from Bristol, added: “It also shows us that dolphins can flexibly adapt their vocalizations to continue to cooperate with their mate, demonstrating that this species is capable of actively coordinated cooperation.”

Sorensen said, “Working together with our colleagues at the Dolphin Research Center in Florida gave us a unique opportunity to study the negative effects of noise on cooperative behavior in a controlled environment, which is nearly impossible in the wild. Our findings highlight the need to account for the influence of noise on group tasks in wildlife.”

Dr King explained: “We show that human-made sound directly influences the success of cooperating animals. If noise makes groups of wild animals less efficient at performing cooperative actions, such as cooperative foraging, this can have important negative consequences for individual health and ultimately for the health of the population.”

Magazine reference:

  1. Pernille M. Sørensen, Abigail Haddock et al. Anthropogenic noise hinders cooperation in bottlenose dolphins. Current Biology. DOI: 10.1016/j.cub.2022.12.063