September 29, 2011

Is there anything fish don't do? Tool use!

This video and story have been making the rounds on the Internet in the last few days. I just saw it yesterday and it's fascinating! For the first time (allegedly), "tool-use" in a fish has been filmed and the behavior is available for all of us to see. The fish in question is a species of wrasse observed in Palau, Choerodon anchorago or orange-dotted tuskfish.

You can see the fish digging out a clam with its pectoral fin, then carrying it over to a rock or a coral head and cracking it with a characteristic sideways motion of the head. The fish was observed doing this three times in a row, the last of which was recorded. Each event lasted less than five minutes. Here are summaries of the story from Scientific American, Science Daily and AnimalWise. This finding is being published as a short notice in the journal Coral Reefs and joins other findings from earlier this year, published in the same journal, presenting the first photographic evidence of the same behavior in another species of tuskfish, Choerodon schoenleinii. That story was summarized in Science Now and Wired Science. In fact, there have been a handful of reports of the same behavior from different species of wrasse indicating that this might be a shared ancestral behavior in the Labridae.

Whether this constitutes "real" tool use as seen in mammals and birds, or not, will depend entirely on the kind of definition you use. That question is boring to me. But I do think it would be a mistake to equate or compare this "tool use" in fish to, for example, tool use in chimpanzees. Instead I think the interesting perspective is to put this behavior within the already known complex feeding and food seeking behaviors in fish to see in which niches "tool use" might have been beneficial.

Bernardi, G. (2011). The use of tools by wrasses (Labridae) Coral Reefs (Online First™, 20 September 2011) DOI: 10.1007/s00338-011-0823-6

Jones, A., Brown, C., & Gardner, S. (2011). Tool use in the tuskfish Choerodon schoenleinii? Coral Reefs, 30 (3), 865-865 DOI: 10.1007/s00338-011-0790-y


  1. I just saw this thanks to Radiolab's tweet - it's the first I'd heard of tool use of any sort by a fish. Thanks for pointing out that this had been previously described in wrasses. I had been wondering why such a discovery would be reported in a journal like Coral Reefs rather than a short communication in something like Science or Nature - I was hoping it wasn't simply a bias against fish, being less charismatic than some mammal or bird species. I think it's still quite surprising. Can you please clarify why you would set this behavior apart from that of chimpanzees using rocks to crack open a nut? Neither involves modification, as in, say the use of twigs for various purposes.

  2. Hey! Thanks for commenting.

    I do suspect there's a bit of a bias against fish. I don't think these kind of findings are that attractive or have enough connection to humans for Nature or Science to be interested. Although the Science website did report on the photos from earlier this year. I put the link in the post.

    As far as I know chimps and several other animals do modify and "shape" their "tools", and sometimes carry them with them for some periods of time. What I meant is that the discussion often goes into what "really" constitutes tool use and what doesn't. If what chimps do is more advanced and can be called tool use (which I don't doubt), or if it's essentially the same thing as fish now have been observed doing, but fish do it in less complex ways, "proto-tool-use" and so on. It's important to have working definitions and to have a comparative approach, but in the end it all almost goes into this competition over which one is the better. I think it's more interesting to study the behaviors within the context of the organism, and the needs its fulfilling by doing the behavior. In that perspective, we already know that fish have many interesting feeding behaviors and it would be fun to see how this "tool use" has evolved within that gamut of behaviors. Then we can really start comparing across a wide range of animals. Clearly the ancestor of both mammals and fish set the stage for the evolution of a nervous system that would be able of "tool use", to some extent, along both lineages.


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