By Mark Brown, Wired UK

Professional diver Scott Gardner has captured what are believed to be the first images of a wild fish using a tool. The picture above, captured in Australia's Great Barrier Reef, shows a foot-long blackspot tuskfish smashing a clam on a rock until it cracks open, so the fish can gobble up the bivalve inside.

[partner id="wireduk" align="right"]Tool use was once thought to be exclusive to humans, and was considered a mark of our superior intelligent and bulging brains. In recent decades, though, more and more animals have shown an ability to work with tools and objects.

Elephants pick up branches with their trunk to swat flies and scratch themselves, a laboratory crow improvised a hooked tool from a wire to extract an insect and primates use sharpened sticks as spears, rocks to smash nuts and sticks to poke into ant nests.

Tool use in fish, however, is much more rare, and there's never been any photo or video evidence to prove it – until now. "The pictures provide fantastic proof of these intelligent fish at work using tools to access prey that they would otherwise miss out on," said Culum Brown of Macquarie University in Sydney in a press release.

"It is apparent that this particular individual does this on a regular basis judging by the broken shells scattered around the anvil," he said in the release.

What specifically constitutes tool use is a controversial topic. Is a seagull using a tool when it drops a shellfish on a rock? How about when archerfish spray a jet of water to knock prey off of twigs? There's also the tricky problem of the ocean having all that watery stuff, and fish having no limbs.

For Brown, though, the blackspot tuskfish counts. "We really need to spend more time filming underwater to find out just how common tool use is in marine fish," he said in the release. "It really is the final frontier down there."

Image: Coral Reefs/Scott Gardner

Source: Wired.co.uk

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