Humpback Whales: the ladies hang out together year after year

Humpback whales - those beautiful songbirds of the cetacean world - may have another behavioral trait that sets them apart from the other baleen whales: the ladies apparently form lasting friendships among themselves - kind of an oceanic "Sex in the City."

According to research being conducted by the Mingan Island Cetacean Study of Canada, along with researchers from Germany and Sweden, when humpback whales return to the Gulf of St. Lawrence following extended periods of migration and breeding, the females congregate in groups to feed - not just any group, but the same group of females year after year. They develop friendships.

While toothed whales, like orcas and sperm whales, have shown similar types of social behavior, baleen whales are much less social. The study, reported in the journal Behavioral Ecology and Sociobiology, reports that no such behavior was seen between blue and fin whales. Only the humpback whale exhibited this bonding between females, bonding that resumed with the return of the whales year after year.

"I was expecting stable associations within one season, not beyond. I was particularly surprised by the fact that only females form these bonds, especially females of similar age," said Dr. Christian Ramp, one of the Canadian leaders of the study. "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 to another one."

What has yet to be determined is how they find each other every year - perhaps by their distinctive songs or some other low frequency sounds which can travel great distances underwater. Another question to be studied is what implications does commercial whaling have on this behavior. Did this bonding in female groups make them easier targets for whalers in the past? If countries that are proposing a resumption of large scale whaling were to have their way, would these friendships among female humpbacks once again make them easy targets? What are the socio-biological implications of disrupting this behavior; how is the overall family structure - hunting, breeding, calving - impacted?

This is another fascinating component in the complex world of marine mammal behavior. Just like a group of women getting together to have lunch and catch up on maybe some juicy gossip. (I'm not being sexist - men do they same thing; they just do it around the tube with a six-pack and a bag of Cheetos!)

Read more about this in BBC Earth News.