EVIDENCE FOR ACQUISITION OF A NOVEL FEEDING-BEHAVIOR - LOBTAIL FEEDING IN HUMPBACK WHALES, MEGAPTERA-NOVAEANGLIAE

The spread of an apparently normal surface feeding behaviour (bubble feeding), which is proceeded by a tail slap, or lobtail (called lobtail feeding), was observed in individually identified humpback whales, Megaptera novaeangliae, feeding on sand lance, Ammodytes americanus, in New England waters during 1980-1989. The proportion of feeding events classified as lobtail feeding was consistent for each individual throughout the entire period that each whale was observed Ninety-five of the 250 whales observed surface feeding used lobtail feeding. The percentage of animals lobtail feeding increased regularly from 0·0% in 1980 to 50·6% in 1989. Over 50% of whales first seen as calves and later documented surface feeding, displayed lobtail feeding, although few of their mothers ever employed this behaviour. Among animals that were first photographed before 1982 only 12·5% were ever seen lobtail feeding. In contrast, 56·2% of animals first photographed after 1982 used the behaviour. No animal was seen to use lobtail feeding before it was 2 years old, although individuals are weaned and separated from their mothers at 1 year. Rudimentary lobtail feeding was witnessed several times among young post-weaning animals. No difference was seen in the frequency of lobtail feeding between sexes. It is hypothesized that this behaviour was initiated as whales switched from feeding on herring to sand lance, and has spread through cultural transmission. © 1992 The Association for the Study of Animal Behaviour.