April 26, 2013
Humpback Whales Learn Hunting Techniques From Each Other
April Flowers for redOrbit.com - Your Universe Online
New research, led by the University of St. Andrews, has found humpback whales are able to pass on hunting techniques to each other, just as humans do.
After herring stocks — their preferred food — crashed in the 1980s, a community of humpback whales off the cost of New England was forced to find new prey. The whales devised a solution by hitting the water with their tails while hunting a new prey. This behavior has now spread throughout the community by cultural transmission. By 2007, approximately 40 percent have been observed engaging in this behavior.
Dr Luke Rendell, lecturer in the School of Biology at the University of St Andrews, said, "Our study really shows how vital cultural transmission is in humpback populations — 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."
Using a new technique called network-based diffusion analysis, the team demonstrated the pattern of spread followed the network of social relationships within the population. This revealed the new behavior had spread through cultural transmission, the same process that underlies the diversity of human culture.
Naturalist observers aboard the many whale-watching vessels that patrol the waters of the Gulf of Maine each summer collected the data used in this study.
Dr Hoppitt noted, "We can learn more about the forces that drive the evolution of culture by looking outside our own ancestral lineage and studying the occurrence of similar attributes in groups that have evolved in a radically different environment to ours, like the cetaceans."
Globally, humpback feeding involves herding shoals of prey by blowing bubbles underwater to create "bubble nets." The new feeding behavior, called "lobtail feeding," involves hitting the water with the tail before diving to produce the bubble nets. First observed in 1980, lobtail feeding seems to be specific to sand lance stocks, which soared as the herring stocks crashed. Scientists believe lobtail feeding is prey specific because its use is concentrated around the Stellwagen Bank spawning grounds where the sand lance can reach high abundance.
The researchers were able track the spread of the behavior through the whales' social network using a unique database spanning thirty years of observations gathered by Dr. Weinrich.
"The study was only made possible because of Mason's dedication in collecting the whale observations over decades, and it shows the central importance of long-term studies in understanding the processes affecting whale populations," Allen said in a statement.
The team believes their results strengthen the theory that cetaceans — whales and dolphins — have evolved sophisticated cultural capacities.