Swimming in Harmony for Safety and Belonging

December 1, 2013
By Tara Haelle

The thought of “synchronized swimming” may call to mind the Olympic event or perhaps white-capped women in old Hollywood musicals. But there’s another mammal that uses synchronized swimming — and it’s not just to show off.

Long-finned pilot whales synchronize their swimming when they sense danger. Researchers made this discovery when comparing two populations of pilot whales, one in the Strait of Gibraltar off the Spanish coast and one near Cape Breton on Canada’s east coast.

Pilot whales use synchronized swimming when they sense danger. Credit: Renaud de Stephanis

Each time the researchers visited a pod of pilot whales, the cetaceans at first swam close to each other, often surfacing and diving close together. But after some time, when other boats (including whale watching boats) were nearby, the pilot whales shifted into more tightly synchronized movements: two whales swam in the same direction, about a body width apart, surfaced together, breathed about a second apart and then dove together.

But there were differences between pods. When the researchers compared one social group to another, either within the same waters or across the Atlantic, the synchronization differed depending on the size and social closeness of the group and the environment.

The researchers suspect that synchronized swimming signals a threat and it may help the whales stay close to one another as they escape. But pilot whales tend to be socially close-knit, and the synchronized behavior may also reinforce their social connections.

Pilot whales aren’t the only marine mammals that use synchronized swimming. Spinner dolphins, killer whales and sperm whales also do it, but biologists are only beginning to understand the reasons.