Two Bowhead Whales in the Arctic Synchronize Their Dives, Showcasing Their Remarkable Long-Distance Communication Skills.
From January to May each year, bowhead whales migrate to Qeqertarsuaq Tunua, a large bay on the west coast of Greenland, to feast on a buffet of plankton. In 2010, two bowhead whales (Balaena mysticetus) entered the bay to feed. When they were approximately 96 km apart, something extraordinary happened: They began to synchronize their dives.
Bowhead whales can synchronize their dives when within communication range. (Photo: Vicki Beaver/Alaska Fisheries Science Center/NOAA Fisheries)
In a newly published study in the journal Physical Review Research, the authors propose that this pair of whales, although unable to see each other, could still hear each other’s sounds. This observation provides potential evidence for a hypothesis that has existed for 53 years, as reported by Smithsonian on October 5.
Bowhead whales are often thought to be solitary creatures. However, some scientists believe they travel in loosely dispersed groups, communicating over distances of hundreds of kilometers. Biologist Roger Payne and oceanographer Douglas Webb first proposed the idea of acoustic social groups in 1971.
According to Evgeny Podolskiy, an environmental scientist at Hokkaido University in Japan and the lead author of the new study, the diving behavior of bowhead whales may initially appear quite chaotic and unpredictable. They undertake dives lasting several hours and then pause for unclear reasons.
Podolskiy and his colleagues aimed to find order within these seemingly random behaviors. Using satellite tracking tags, the research team collected data on the dive depth and location from 12 bowhead whales in the Arctic over 144 days. They then applied complex algorithms based on chaos theory. During their calculations, patterns began to emerge.
First, the research team discovered that the whales’ dives tended to follow a 24-hour cycle, being shallower in the morning and deeper in the afternoon. This aligns with the Daily Vertical Migration (DVM) phenomenon, which involves the journey from the ocean’s surface to the deep sea and back by plankton and other small creatures. They also found that the whales performed their deepest dives in the spring when DVM is most pronounced in the Arctic.
However, what surprised Podolskiy was the second pattern: the synchronized dives of the pair of bowhead whales in Qeqertarsuaq Tunua. The research team is unclear about their relationship, yet they synchronized their dives for seven consecutive days while being within 96 km of each other. According to the team’s calculations, that is the maximum sound range for whales in the area. “This is an extremely strange behavior underwater. It’s very intriguing,” Podolskiy stated.
Podolskiy also added that this synchronization might just be a coincidence. It is possible that oceanic conditions prompted the whales to dive simultaneously at different locations. However, the fact that synchronized diving occurred continuously over several days makes that possibility statistically unlikely. “Currently, we believe it relates to communication”, he said.
