As a result of noisy ship engines and the racket of ocean mining, bottlenose dolphins have slowly reducing the complexity and changing the frequency of their calls. According to new research from the University of Maryland Center for Environmental Science and published in the journal Biology Letters, "the noise-induced simplification of dolphin whistles may reduce the information content in these acoustic signals and decrease effective communication, parent–offspring proximity or group cohesion." From YaleEnvironment360:
“It’s kind of like trying to answer a question in a noisy bar and after repeated attempts to be heard, you just give the shortest answer possible,” Bailey said. “Dolphins simplified their calls to counter the masking effects of vessel noise.”
Dolphins are highly social animals and use their calls to stay together as a group, talk as they feed, and call out their names when they meet new members of their species. Each animal has a distinctive whistle, which typically uses complex sound patterns with variations in pitch and frequency.