Dolphins Found To Be Using Tools To Forage

Dolphins on the West Coast of Australia have been found to use tools for foraging, report scientists from the Universities of Zurich and New South Wales in Sydney. It is the first time documented evidence has been gathered to examine how dolphin societies and communities exist.

Scientists discovered that the Bottle-nosed Dolphin (Tursiops truncatos) at Shark Bay in Western Australia uses around 12 alternative methods to forage for food - some dolphins loosen sponges from the sea bed and put them over their noses in order to protect their nose when they are looking for food on the sea bottom. Among the whole population of 3000 dolphins at Shark Bay only 30 belong to the group of the so called spongers, explained Michael Krützen, scientist at the Institute for Anthropology of the University Zurich.

The researchers wanted to clarify, why only a small minority of dolphins, most often females, used the sponge technique for foraging. They analyzed the inherited material of 13 dolphins that used sponges, and of 171 animals that didn’t. Among the 13 spongers there was one male animal. Researchers detected that neither genetic nor environmental factors played a role.

The scientists believe the special behaviour is passed on from the mother to the daughter. The spongers displayed a significant genetic relationship.

“That’s why we assume, that fishing with sponges was invented by a female ancestor a relatively short time ago”, said Krützen. Detailed results of the research will be published in the magazine “Proceedings of the National Academy of Sciences of the USA”.

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