A UNIVERSITY of WA-led study has found male dolphins’ shared interest in using marine sponges to get food strengthens their friendships.
“Foraging with a sponge is a time-consuming and largely solitary activity, so it was long-thought incompatible with the needs of male dolphins in Shark Bay to invest time in forming close alliances with other males,” researcher Manuela Bizzozzero, from the University of Zurich, said.
However Ms Bizzozzero said the sponge-using mammals, which shared the tools and taught each other their use, showed a social system of alliances.
“These strong bonds between males can last for decades and are critical to each male’s mating success,” she said.
From 2007 to 2015, the team of Crawley, Zurich and Bristol researchers looked at 37 male Indo-Pacific bottlenose dolphins in Shark Bay, about 650km north of Perth.
The group consisted of 13 which used sponges, and 24 which did not, to get food.
The University of WA School of Biological Sciences’ Simon Allen said the sponges helped the mammals find food in deep water.
The skill was passed between generations.
It was discovered male sponge users spent more time with other male spongers.
The bond was based on use of similar feeding techniques rather than if they were related or any other factor.
“This study suggests that, like their female counterparts and indeed like humans, male dolphins form social bonds based on shared interests,” Dr Allen said.
The finding will be published in the Proceedings of the Royal Society.