Just because they can’t sing opera or ride a unicycle doesn’t mean that animals don’t have culture, and there’s no better example of this than the killer whale. As one of the most brutal predators on the planet, orcas may not fit the profile of a cultured creature. However, these beasts of the sea do display a vast range of highly refined behaviors that appear to be driving their genetic development, according to new research.
The word “culture” comes from the Latin “colere,” which literally means “to cultivate.” In other words, it refers to anything that is acquired or learnt, rather than instinctive or natural. Among human populations, culture not only affects the way we live, but also writes itself into our genes, affecting who we are.
For instance, having spent many generations hunting the blubbery marine mammals of the Arctic, the Inuit of Greenland have developed certain genetic adaptations that help them digest and utilize this lipid-rich diet, thereby allowing them to thrive in their cold climate.
Like humans, killer whales have colonized a range of different habitats across the globe, occupying every ocean basin on the planet, with an empire that extends from pole to pole. As such, different populations of orcas have had to learn different hunting techniques in order to gain the upper hand over their local prey. This, in turn, has a major effect on their diet, leading scientists to speculate that the ability to learn population-specific hunting modalities could be driving the animals’ genetic development.
Publishing their findings in the journal Nature Communications, an international team of scientists explain how they analyzed the genomes of 50 orcas from five different populations, inhabiting a range of locations in the North Pacific and Antarctic Oceans.
Among the whales included in the study, some came from populations known to feed mainly on penguins, some ate a diet consisting mostly of mammals and others feasted on fish. After examining their genetic make-up, the researchers found that the orcas fit into five neat ecotypes, or genetically distinct geographic varieties of whale, thereby indicating just how synchronized their genes are with their culture.
They suggest this has occurred as populations have developed highly specialized, often ingenious hunting techniques – such as the creation of artificial waves in order to knock seals off ice floes, as made famous by the BBC’s Frozen Planet documentary series. By teaching these strategies to their young, the whales have developed a deep-rooted culture, reinforcing their diet and leading to certain selective pressures upon their genes.
For example, fish-eating ecotypes were found to carry certain genes that enabled them to more effectively digest their scaly prey, while those that hunt blubbery mammals were more genetically attuned to this fatty diet.
All in all, the study authors suggest that “culture-genome evolution” may not be exclusive to humans after all, and urge other researchers to place more focus on the role of animals’ culture in driving their genetics.
