Call me spongeface – dolphins off Western Australia carry sponges on faces – Breakthroughs

Call me spongeface – dolphins off Western Australia carry sponges on faces – Breakthroughs – Brief Article

When a team of American and Swedish biologists observed a dolphin with a cone-shaped sponge over its beak in Shark Bay, off Western Australia, a few years ago, they thought they were witnessing the quirky behavior of a lone dolphin. Since then, however, the biologists have found several Shark Bay dolphins carrying sponges. “Some of the sponges are really great big things that flop around and cover part of a dolphin’s face,” says Rachel Smolker, a behavioral ecologist at the University of Vermont. So why would the dolphins burden themselves with something that increases their drag and might also interfere with their echolocation abilities, which they use for orientation and hunting? Smolker isn’t sure but suspects that the dolphins use the sponges as a foraging tool. The sponge may protect them from the spines of stingrays, lionfish, or prickly prey. Or it may protect their beaks from abrasion while poking in the sandy bottom to flush out burrowed animals. Most of the dolphins in Shark Bay, however, don’t use sponges. “It could be that only a few do it because it takes a lot of skill,” says Smolker. Or, she says, it may be that “there is some kind of dominance and some dolphins are forced into a less lucrative foraging area” and have to use special techniques to hunt successfully.

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