Scientists report on a tool-using fish

Researchers say they have evidence of a fish using a tool. Diver Scott Gardner captured images of the tool-wielding tuskfish in Australia’s Great Barrier Reef.

Researchers from Macquarie University and Central Queensland University say they have evidence of a fish using a tool. The fish was captured on film by diver Scott Gardner in Australia’s Great Barrier Reef.

This fish appears to be smashing molluscs open on an anvil-shaped portion of a rock, in order to get to the treat inside. The images of this, the scientists say, offer the first-known glimpse of a fish using a tool in the wild. The researchers documented this marine tool-use in late June 2011 in the journal Coral Reefs.

The scientists say the tool-wielding fish is a black spot tuskfish, or Choerodon Schoenleinii. The sighting and images by Scott Gardner prompted the scientists’ paper. Co-author Culum Brown of Macquarie University said in a press release:

The pictures provide fantastic proof of these intelligent fish at work using tools to access prey that they would otherwise miss out on

The scientists say the tuskfish was aggressively moving its head around to land alternate blows on the cockle it was holding in its mouth. And this, they say, meets the definition of tool use as outlined by Jane Goodall, the famed primatologist and conservationist. The scientists said:

Jane Goodall describes tool use as the use of an external object as a functional extension of mouth or hand in the attainment of an immediate goal. Tool use is often observed in a foraging context in a wide range of species, [but] there are few documented cases of [the use of tools by marine fishes], particularly based on observations by those in the wild.

The footage of this high-IQ fish was first obtained in 2006 by Scott Gardner, who turned when he heard a “cracking” noise, underwater. The tuskfish (and/or other fish, or other unidentified creatures) appear to have used that same rock as a tool, before, according to Gardner. That’s because, he said, there was a big pile of smashed shells next to the rock.

Fish might be smarter than we think, according to Dr. Culum:

We really need to spend more time filming underwater to find out just how common tool use is in marine fish. It really is the final frontier down there.

Other mammals known to use tools include elephants, which hold branches with their trunks to swat at flies, and birds, which sometimes use improvised hooked tools to suss out insects.

The Australian researchers’ claim about tool use by the tuskfish has opened up a debate about what exactly a “tool” is, and whether the fish was using one. Deborah Braconnier of PhysOrg.com framed it nicely:

While the tuskfish is clearly using the rock to break the shell, it is never really “holding” the tool itself. Many scientists argue that this is essentially not tool use. However, Brown argues that this definition of tool use would restrict any possibility to only animals with an anatomy similar to humans. Fish do not have hands and the ability to use a rock to swing at the shell, so they use what they can. To look at the debate in another way, think of humans that are born without, or lose, their arms and legs. They no longer have the ability to swing a tool in the traditional way, but because they may use their mouth to accomplish a task, does that make them any less capable of tool use?

Bottom line: Researchers from Macquarie University and Central Queensland University discovered a tuskfish smashing molluscs open on an anvil-shaped portion of a rock, in order to get to the treat inside. The scientists say their images of this fish offer the first-known glimpses of a fish in the wild using a tool. The researchers documented this marine tool-use in late June 2011 in the journal Coral Reefs.

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