New research indicates that humpback whales might be learning new behaviors through socialization, a controversial claim in the realm of cetaceans.
Luke Rendell, a marine biologist with the University of St. Andrews in Scotland, co-authored the study. A proponent of cultural transmission amid cetaceans, Rendell and his team explored a pattern of feeding habits displayed by a group of humpbacks in the Gulf of Maine around New England, U.S. They tracked the behavior using data collected via observers with the Whale Center of New England from 1980 to 2007.
The feeding pattern involves what is termed “lobtail” feeding, first recorded in Maine in 1980. Now almost 40 percent of the whales that occupy the Stellwagen Bank area near Boston are utilizing the lobtail method.
To understand why lobtail feeding is important, one must first be familiar with the eating habits of humpback whales. Humpbacks originally ate a great deal of herring, which they caught through the technique of bubble-net feeding (a method of blowing bubbles that creates a “net” and gathers prey into dense groups; the whale then dives through the net and consumes the catch). Around 1980, however, herring populations suffered a severe drop.
Due to the depletion of herring, humpbacks began eating sand lances, another type of fish. It was at this time that lobtailing began. Rendell suspects it has to do with keeping sand lances from escaping the whale during feeding, as the whale slaps the water one to four times with its tail before diving and casting its bubble-net. According to the data from the Whale Center, the growth of lobtail feeding was proportional to sand lance hunting.
Rendell believes the behavior passed through socialization; if one humpback in a group began to lobtail, others would as well. Some critics view the data—which was, again, gathered through observation and not by any other experimental means—as insufficient for the claim that humpbacks share a social culture. Rather, they just happened to all learn the technique at roughly the same time.
Others are less skeptical. Simon Reader, a biologist with the McGill University in Quebec, Canada, suspects there could be other reasons for the spread of lobtail feeding, but agreed that Rendell’s evidence did favor social learning.
As per Science Daily: “Our study really shows how vital cultural transmission is in humpback populations,” said Rendell. “Not only do they learn their famous songs from each other, they also learn feeding techniques that allow them to buffer the effects of changing ecology.”
The St. Andrews team’s findings are detailed in the newest edition of the journal Science.