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Anew survey suggests that some whales and dolphins have cultural and social lives as rich and complex as those of primates.
Biologists have compiled details of the social and cultural behaviour of 90 species of whale and dolphin, including regional song dialects, individual signature whistles, cooperative hunting and group defence and communal rearing of young.
The survey confirms that increasing social and cultural complexity has gone hand in hand with an increase in brain size, with large-brained species such as killer, sperm and humpback whales displaying the most flexible behaviours.
“The apparent co-evolution of brains, social structure, and behavioural richness of marine mammals provides a unique and striking parallel to the large brains and hypersociality of humans and other primates on land,” says Susanne Shultz of the University of Manchester. “Unfortunately, they won’t ever mimic our great metropolises and technologies because they didn’t evolve opposable thumbs.”
The gap between human and cetacean society is more than material, though. What about art, poetry, philosophy and politics?
“Without a fully developed language, which we assume they do not have, it is unlikely that they would have symbolism,” says Shultz. “So, dolphins and relatives are far away from humans, but they do have a cultural richness not seen in most animal groups.
“Of course we don’t think they are equally sophisticated,” Shultz adds. “What we do argue is the social organisation combined with brain size evolution lead to an increase in behavioural ‘tool kits’.”
It is just such tool kits, say the biologists, that have given killer whales the cultural and behavioural flexibility to fill niches in widely different habitats and conditions from the poles to the tropics, adapting their diets and hunting strategies accordingly and passing them on as traditions.