The scientists suspect that behavioral flexibility in both animal groups leads to cultures inherited through social learning over many generations. As time goes on, genetic changes that may contribute to the adaptations can also rise in frequency and gradually become widespread throughout the population as it expands. Cultural and genetic change therefore go hand in hand, but the behavioral flexibility that leads to the former probably happens first.
Orca experts contacted by Discovery News said that the new paper represents a milestone in marine mammal research.
Hal Whitehead, a biologist at Dalhousie University, said, "I had hoped for some time that someone would begin to look at gene-culture coevolution in killer in killer whales using genomics, but the extent of this research goes beyond well my hope. The results are fascinating. We now see how in killer whales, as in humans, culture is not only an important factor in the lives of the whales, but also drives genetic evolution."
Michael Krützen of the University of Zurich's Anthropological Institute & Museum said, "So far, we have not been able to investigate the link between adaptive evolution and the demographic history of a marine mammal species in such great detail. The genomics analyses are state of the art and allowed novel insights into the processes shaping the genome of a marine mammal."
Krützen added that "there is no reason to assume gene-culture co-evolution is not also happening in other highly cultural species, such as for instance great apes and some marine mammals." Future studies might therefore apply the same approach to other intelligent, social animals, such as bottlenose dolphins, which also exhibit gene-culture coevolution.