FEMALE OF THE SPECIES

To sponge or not to sponge? That is the question for the bottlenose dolphins (Tursiops aduncus) living in Shark Bay, Western Australia.

- Lucy Cooke

These super-smart cetaceans have learnt a crafty trick when foraging for grubfish, which hide away on the seabed. To locate this cryptic prey, they use their snouts to probe the sand and encourage the fish to reveal themselves. A dolphin’s snout, or rostrum, is packed full of nerve endings and extremely sensitive to touch. So, sifting through grit must be an irritating occupation. Which is why some dolphins have started wearing marine sponges for protection.

This functional fashion was first recorded in 1995 in five dolphins. It caused a scientific stir as the only known instance of tool-use by dolphins in the wild. Since then, ‘sponging’ has spread to one third of the dolphin population. Scientists at the Shark Bay Dolphin Research Project have been trying to figure out how this ingenious culture is transmitted, and why it’s mostly females that take it up.