Dolphins can teach each other how to hunt more effectively using traps, scientists observed in a new study, suggesting the animals have a high level of social learning and intelligence on a par with apes.
The study, published in peer-reviewed science journal Current Biology last week, observed bottlenose dolphins “shelling” - a technique where a dolphin traps prey in a large empty shell before bringing it to the surface and shaking it vigorously so the fish falls into their mouths.
Resarchers found that the dolphins, who reside in Western Australia’s Shark Bay, transmitted the knowledge of shelling to other dolphins of the same generation, such as between siblings or friends, rather than parents, such as mother to calf – the first known example of horizontal knowledge spread.
“These results are surprising, insofar as vertical social transmission between mother and offspring has been established as the primary mechanism for learning foraging behaviors in Shark Bay’s dolphins,” the researchers wrote in the study.
Shark Bay dolphins have also been observed putting sponges on the end of their noses to protect them while they dig for prey from the seafloor. The transmission of this knowledge, however, has only been seen being transmitted from mother to calf and is more common than shelling.
The existence of horizontal behaviors, however, does suggest that dolphins possess a high degree of social intelligence, similar to that of great apes such as chimpanzees, gorillas and orangutans.
“Extensive work on primate culture has shown that horizontal transmission of foraging behavior is biased toward species with broad cultural repertoires and those with increased levels of social tolerance, such as great apes,” the researchers wrote.