As one of the smartest creatures on earth, dolphins can do some incredible things. When it comes to foraging skills, it has long been thought that dolphins only learn them from their mothers. But scientists now find that they can also learn these skills from peers, providing the first evidence for this so-called “horizontal social teaching.”
The study, led by Dr Sonja Wild and part of a PhD programme at the University of Leeds, focuses on the behaviour of a group of dolphins in Shark Bay off the coast of Western Australia. Research in the 1990s revealed a fascinating behavior among these creatures, with scientists observing a never-before-seen foraging technique, called shelling.
During the “shelling” process, the dolphins sniffed out prey hidden in the shell left behind by a giant conch, biting it with their mouths and taking them to the surface. Once there, they shake shells and empty them, just as you would empty the last few chips from the package to get their food. This behavior is thought to be passed from the mother dolphin to the baby dolphin, which scientists call vertical social instruction.
International teams investigated the “shelling” of Shark Bay dolphins on board from 2007 to 2018, and they found 1,035 individual animals and recorded a total of 42 “shelling” behaviors by 19 different dolphins. Behavioral, genetic and environmental data were then used to track the course of the behavior, which the team concluded was indeed learned from peers.
“These results are quite surprising because dolphins tend to be conservative, and small dolphins follow the ‘mother-to-mother’ strategy to learn foraging behavior,” Wild said. “However, our results show that dolphins are absolutely capable and, in the case of shelling, have the incentive to learn new foraging strategies outside of the mother’s relationship. This opens a door for us to gain a new understanding of how dolphins adapt to changing environments in behavior, because learning from peers allows new behaviors to spread rapidly across populations. “
According to the team, this is the first quantitative evidence of horizontal teaching of toothed whale foraging strategies, similar to the learning behavior of apes, chimpanzees and, of course, humans.
“The fact that shelling is socially transmitted between dolphin companions, rather than between mothers and offspring, sets an important milestone and highlights similarities with certain primates that also rely on foraging behaviour for which vertical and horizontal learning is also dependent on,” said the study’s senior author, Professor Michael Krtze?n of the University of Zurich. “Despite their different evolutionary histories, they occupy such different environments: dolphins and great apes are long-lived brain mammals with high innovation and cultural heritage of behavior. “
The study was published in the journal Current Biology.