The first tool-using (?) fish

Many species, including crows, chimps, and capuchin monkeys, are known to use tools, but a new paper in Coral Reefs by A. M. Brown et al. (paper free at link and highlighted in Science NOW) reports what may be the first documented case of a tool-using fish.

On November 12, 2006, one of the authors (Gardner), diving off the Great Barrier Reef, observed a black spot tuskfish, Choerodon schoenleinii, holding a cockle in its mouth and repeatedly striking it against a rock until the shell broke.  This was documented photographically below:

According to Science NOW, this is apparently not a one-off behavior:

The tuskfish caught on camera was clearly quite skilled at its task, “landing absolutely pinpoint blows” with the shell, Brown says. A scattering of crushed shells around its anvil rock suggests that Gardner didn’t just stumble upon the fish during its original eureka moment. In fact, numerous such shell middens are visible around the reef. Blackspot tuskfish, members of the wrasse family, are popular food fish, so it’s surprising that its shell-smashing behavior has remained unknown, Brown says. “My feeling is that when we go out and really look for it, it’ll turn out to be common.”

Now whether you see this as “tool using” of course depends on your definition of “tools.”  Italian primatologist Elisabetta Visalberghi says that this is not tool-using because her definition “requires the animal to hold or carry the tool itself,” and this fish didn’t carry the rock.  In fact, that kind of tool use would be impossible for most marine species, however smart (cephalopods are an exception).  But it is tool use according to the definition of Jane Goodall quoted by the authors: “the use of an external object as a functional extension of mouth or hand in the attainment of an immediate goal.

I’m not quite clear why animal behaviorists argue so strongly about what constitutes a tool.  What seems more important to me is whether an animal has the cognitive and learning capacity to use things in its environment to fulfill its “desires.”  Whether or not it carries things to do that seems to be a tangential issue.

Regardless, if this is a learned behavior (and I suspect it is), then it says something new about the intelligence of fish.


Jones, A. M., C. Brown and S. Gardner. 2011 Tool use in the tuskfish, Choerodon schoenleinii.  Coral Reefs: DOI 10.1007/s00338-011-0790-y


  1. Posted July 11, 2011 at 5:19 am | Permalink

    I think that as a primatologist, Visalberghi may have a bias that leads to an exclusionary definition of a tool. Fish don’t have hands, right? Yes, there are lobes, but c’mon, tool use limited to hands?

    Talk about privileging.

  2. Posted July 11, 2011 at 5:36 am | Permalink

    JAC quote: “…if this is a learned behavior (and I suspect it is)…”

    Why do you suspect that it is learned behavior ?

    • ChasCPeterson
      Posted July 11, 2011 at 6:06 am | Permalink

      good question.
      More: Learned when and from whom?

      Learning by observation is very difficult (i.e. mostly impossible) to demonstrate, even in laboratory primates. Intentional teaching is even rarer, chimps only afaik.
      It would be a huge deal in any fish.

      • Matt G
        Posted July 11, 2011 at 9:20 am | Permalink

        Meerkats, too. They aren’t mere cats, you see.

      • Marlene Zuk
        Posted July 11, 2011 at 9:45 am | Permalink

        Also ants:

        There’s been a fair amount of discussion about this among animal behaviorists, since obviously ants don’t have the cognitive abilities of chimps or meerkats. But I think the tandem running as teaching is now pretty well accepted.

        • Kharamatha
          Posted July 12, 2011 at 2:39 am | Permalink

          Sometimes tool use is amusingly puffed up as something super-duper complex that couldn’t possibly be done without an officially recognised Ph.D. in engineering.

          There was a Chicken-something on Youtube who argued that a chimp wasn’t using a spear because it had only sharpened one end of a stick. It’s just a sharp stick, I tells you! Not a spear!

          And I once got into an argument with an “humans are the only animals who don’t live in harmony” person who did say that chimp massacres don’t count as warfare for the explicit reason that they did not write declarations of war and file the paperwork.

          • Kharamatha
            Posted July 12, 2011 at 2:40 am | Permalink

            “an” -> “a”
            Arrgh, curse you, non-editing!

          • Posted July 12, 2011 at 3:49 am | Permalink

            We don’t declare war, either, except on concepts like “terror”.

            • Posted July 13, 2011 at 6:08 am | Permalink

              Ah, right. Otherwise it’s just a Freedomifying Event Operation.

              • Posted July 13, 2011 at 6:10 am | Permalink

                Damn, I realised too late that it could have been FOE.

                Even in the blogosphere; F.O.E.!

  3. Dominic
    Posted July 11, 2011 at 5:36 am | Permalink

    PZ will live this line “cephalopods are an exception”!

    Perhaps it says something about what we call ‘intelligence’? Is intelligence not more about self consideration, self refection, contemplation of existence as a being than just tool use? Perhaps intelligence is as illusory as free will!

  4. daveau
    Posted July 11, 2011 at 5:53 am | Permalink

    Can’t let the spousal unit see this. Then she’ll stop eating fish, too.

    • Dominic
      Posted July 11, 2011 at 9:00 am | Permalink

      I would not think she will be too happy being called the ‘spousal unit’ either! 😉

      • daveau
        Posted July 11, 2011 at 9:25 am | Permalink

        Just “unit” then?

        • David Robin
          Posted July 11, 2011 at 2:05 pm | Permalink

          SWMBO! (Just ask Rumpole).


  5. Corda
    Posted July 11, 2011 at 6:39 am | Permalink

    Are there any apparent adaptations for the behavior? Like a jaw structure for gripping shells, or harder bones for more effective blows against rocks?

  6. Posted July 11, 2011 at 6:50 am | Permalink

    What about archer fish using jets of water as a “tool”?

    • whyevolutionistrue
      Posted July 11, 2011 at 7:38 am | Permalink

      Actually, that issue is mentioned in the Science Now piece. It’s not considered a tool, I guess, because water drops aren’t “objects”, I guess, though it’s certainly on the continuum of “using parts of the environment to get what you want.”

      • Gregory Kusnick
        Posted July 11, 2011 at 10:24 am | Permalink

        A rose climbing a trellis is arguably “using part of the environment to get what it wants,” but presumably we’re not going to call that tool use.

        On the flip side, if a spider built its web from found bits of string instead of from its own secretions, surely that would count as tool use.

  7. Posted July 11, 2011 at 7:41 am | Permalink

    When my cat has a piece of feces stuck on her butt, she rubs her butt on the carpets to dislodge the feces. If we go by these authors’ definition, my cat’s behavior is also an example of tool use.

  8. sponge bob
    Posted July 11, 2011 at 7:53 am | Permalink

    I can’t hold a millstone with my hands but can still use it as a tool to grind grain.

    I don’t see why using a stationary rock isn’t tool use.

    I also drop bags of ice on the concrete floor to loosen the cubes up. The floor is clearly a tool used to get beer cold.

    • Sajanas
      Posted July 11, 2011 at 9:28 am | Permalink

      So, the eagles that open turtles by carrying them up and dropping them are using the ground as tool?

      I suppose I’d consider the fish to be using a tool if they made an effort to select a good rock for opening their shells. Just beating it on whatever rock is handy seems more like environmental use, and is an interesting behavior, but its not quite in the same league as selecting an object from many (and potentially manipulating it) and preferentially using it for a task.

      On a side note, do people consider otters cracking open shells with rocks to be tool use?

      • sponge bob
        Posted July 11, 2011 at 1:21 pm | Permalink

        I think even more impressive than tool use is tool forming.

        Lots of animals use external things to achieve a goal, but very few actually form a tool that I know of. Crows can, and that is cool.

        • Kharamatha
          Posted July 12, 2011 at 2:46 am | Permalink

          Corvids are great. 🙂
          And yes, crafting tools, and selecting a tool before it is needed, maybe even carrying it just in case, are more impressive behaviours.

  9. jay
    Posted July 11, 2011 at 7:55 am | Permalink

    “requires the animal to hold or carry the tool itself,” and this fish didn’t carry the rock. ”

    hmmm by that definition a table saw is not a tool… who’d a thunk

  10. Sili
    Posted July 11, 2011 at 8:00 am | Permalink

    So if I bang a rock on a coconut, I’m using a tool, but if I bang a coconut on a rock, I’m not?

    • Posted July 11, 2011 at 8:06 am | Permalink

      That would seem to be the case according to some animal behaviorists! Good point.

  11. Posted July 11, 2011 at 9:16 am | Permalink

    If they learn how to use guns, I’m giving up fishing.

  12. hexag1
    Posted July 11, 2011 at 9:56 am | Permalink

    I think its silly. If we use that standard for tool use, then even raptors that pick up their prey and drop it to kill it or break it open (like for clams and mussels etc) are tool users.

  13. bacopa
    Posted July 11, 2011 at 11:04 am | Permalink

    I think this thread is going to go a long while. I will decline to try to attempt a definition of tool use. I will simply point out that this is a more sophisticated behavior than the the “head bash” routine that monitor lizards and kingfishers use to kill their prey. Birds and reptiles who do this simply shake their heads in a U-shaped motion until their prey is knocked out by having its head bashed on the ground or perch.

    This fish does something more complex because it has to decide what to ram the cockle into. Ramming it into the silt just won’t do.

    Some of you may not know this, though most of you probably do. You may have seen cockle shells on a necklace. That little hole in the shell was not drilled by a jewelry maker. It was drilled by a whelk that injected its digestive juices through that hole and sucked it out through that hole.

  14. Rikki
    Posted July 11, 2011 at 1:03 pm | Permalink

    The very limited definition of tool use is often commandeered by certain primatologists, who desperately seek evidence for declaring primates more advanced than lowly reptiles/fish/invertebrates.

  15. MadScientist
    Posted July 11, 2011 at 3:08 pm | Permalink

    In Asia I’ve seen folks using a sharpened wooden stick fixed in the ground to remove coconut husks. I guess the sharpened stick wouldn’t be considered a tool by some people since the folks using it don’t hold it. I guess tapping a husked coconut on a hard surface to crack it isn’t tool use either. I wonder why there is such variation in the definition of tool use.

  16. Marella
    Posted July 11, 2011 at 4:17 pm | Permalink

    An engineer I know describes a house as “a tool for living”, by this definition a burrow or a nest is a tool, to say nothing of a beaver’s dam, and one the animal has made itself. I don’t see how a spider’s web could be other than a tool for catching dinner either.

    • Adam
      Posted July 11, 2011 at 8:27 pm | Permalink

      When the tool comes out of spinnerets on your backside I’d hesitated to call it a “tool”.

      • Gregory Kusnick
        Posted July 12, 2011 at 9:43 am | Permalink

        Why should that matter? A rope made from human hair is just as ropy as one made from grass. A bone awl is just as effective as a wooden one (maybe more so). Lots of tools are made from biological materials; I don’t see that using your own secretions is inherently less toolish than using somebody else’s.

  17. Posted July 11, 2011 at 6:04 pm | Permalink

    Hexad1’s point at #11 is well-taken – it seems a bit of a stretch to extend the meaning of tool to include the surface of the Earth but as Jerry pointed-out – the cognitive ability required is important to consider: the raptor apparently has the ability to anticipate the outcome of dropping its prey and it would have to judge the required height as well. Perhaps raptors experiment, as youngsters, learning through trial and error – and how did the bird arrive at the concept in the first place? Seagulls also engage in this behavior.
    If Jane Goodall’s broad definition of tools becomes accepted, we’re going to have to qualify our term(s) whenever we discuss tools or tool-use. Could a tree branch, thrown by a chimp, to chase a snake away, be considered another example of tool use by chimps? Do the found objects that bower birds use to decorate their bower, to attract a mate, qualify as tools? And does it matter whether or not the behavior is innate – the bird certainly appears to be evaluating the possible effectiveness of his work as he walks about looking at it and re-arranging it. Is he considering it from a female’s perspective or is there some innate “correctness” that he’s compulsively striving towards?

    • Torbjörn Larsson, OM
      Posted July 11, 2011 at 7:26 pm | Permalink

      As for the chimp throwing things, I would suggest repeated use.

      One wildlife park here [Sweden] IIRC has or had an ape that collects rocks into piles to later throw at visitors when he/she gets bored. That is IMHO a tool for a set purpose. OTOH that wasn’t to fulfill an “immediate goal” but a future “desire”.

  18. Ilya
    Posted July 11, 2011 at 9:02 pm | Permalink

    On the topic of tool use by apes – classic example from BBC

  19. Posted July 12, 2011 at 1:49 am | Permalink

    When I first read about this sort of behaviour last year in Practical Fishkeeping (reporting on Lukasz Pasco of the University of Wroclaw in Poland’s paper, Tool-like behavior in the sixbar wrasse, Thalassoma hardwicke, I found myself surprised by the fact it was news. My moon wrasse (Thalassoma lunare) often engaged in the same behaviour to break up large foods. Here’s a poorly shot video of her:

    So I had the same genus performing the behaviour. Add the tuskfish, and you have three species of wrasse doing it.

    I’ve never noticed similar behaviour in the other species in my collection, including other Great Barrier Reef fish as well as African cichlids.

    • Posted July 12, 2011 at 1:51 am | Permalink

      Hmmm… Embed failure. Try

  20. Dr. I. Needtob Athe
    Posted July 17, 2011 at 3:03 pm | Permalink

    Here’s a post on Democratic Underground where a user reports crows dropping nuts on a road so that cars will run over them and crack them open:×1507122

4 Trackbacks/Pingbacks

  1. […] in to Jerry Coyne’s Why evolution is true, I noted mention of a news article at Science on tool-like behaviour in fish. It describes a […]

  2. […] unfolded in one of my favorite blogs, “Why Evolution is True” by Jerry Coyne, who also took note of this recent discovery (indeed, I first learned about it there).  The comments below make for some interesting reading, […]

  3. […] The first tool-using (?) fish […]

  4. […] other animals. For example, tool use has been observed in numerous birds, a species of dolphin, a fish and even an invertebrate. These examples all serve to put into perspective the nature of those […]

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