We’ve long known them to be highly intelligent and at-least somewhat social creatures. But a surprising set of results from studies conducted by Canada’s Mingan Island Cetacean Study (MICS) indicates that humpback whales are capable of forming social bonds (for lack of a better term, let’s call them friendships) that are reestablished annually and maintained over periods of several years.
News of the discovery is reported by BBC, which indicates that patterns of protracted social bonds have been observed in some species of toothed whales as well as in the bottlenose dolphin, but whales of the baleen variety such as the humpback have not been understood to form and maintain such linkages before now. The research, currently published in the journal Behavioral Ecology and Sociobiology, was undertaken by Christian Ramp and MICS colleagues along with contributions from scientists visiting from Germany and Sweden. The research group tracks the migratory movements and behaviors of several whale species, having crafted an observational database that stretches back three decades.
As BBC reports, the researchers relied upon photographic identification to keep tabs on individual humpbacks as they would return to the Gulf of St. Lawrence for summer feeding. While the humpbacks would disperse during the rest of the year living in relative isolation to breed and birth calves, the summer period finds the same individual whales getting together, spending time in each other’s company, swimming and feeding. The MICS team finds that these bonds tend to be expressed among females who are approximately the same age, and the longest-lived bonds found so far to exist between individual whales goes back six years.
Precisely how the whales recognize each other, whether through visual or auditory clues, is uncertain although the latter is strongly suspected to explain how they find each other after several months apart. Nor is it known what evolutionary purpose is served by the social bonds, although the researchers note that the whales who are observed to have and maintain consistent social ties with other whales tended to birth more calves than average. Improved efficiency of feeding that is allowed by banding together appears to be an additional benefit Dr. Ramp tells BBC:
“Staying together for a prolonged period of time requires a constant effort. That means that they feed together, but likely also rest together. So an individual is adapting its behaviour [sic] to another one.”
Photo by NOAA via Wikimedia Commons