Dolphin Speak

A research project has distinguished nearly 200 different whistles that dolphins make, linking some of them to specific behaviors. Liz Hawkins of Southern Cross University in Lismore, Australia, has concluded that their communication is “highly complex and it is contextual, so in a sense, it could be termed a language,” as she told the magazine New Scientist.

Hawkins recorded a total of 1,647 whistles from 51 different pods of dolphins living in Byron Bay, just south of Brisbane. She identified 186 different whistle types. Of these, 20 were especially common.

Dolphins use “signature” whistles to identify themselves to others and refer to each other in their whistles, something no other animals are known to do. But they are apparently saying much more. When a pod was traveling, for instance, 57 percent of the whistles were “sine” whistles, rising and falling symmetrically. But when the dolphins were feeding or resting, they made far fewer whistles of this type. And while socializing, they communicated almost exclusively using flat-toned or rising-toned whistles.

The dolphins often made a particular flat-toned whistle when they rode the waves created by Hawkins’s boat, and it’s tempting to speculate that the whistle is the equivalent of a child going “wheeee!” In a group of dolphins living off Queensland, Hawkins identified a whistle often emitted by an animal when it was on its own. “That whistle could definitely mean: ‘I’m here, where is everyone?’” says Hawkins.

Melinda Rekdahl of the University of Queensland found dolphins make more whistles when they’re being hand-fed than those feeding in the wild. “It’s too early to know whether whistles might mean something as specific as ‘hurry up’ or ‘there’s food over here,’” she says. “But it’s possible. Dolphin communication is much more complicated than we thought.”

A review of the science of dolphin communication can be found at http://acp.eugraph.com.