Fish mimics a mimic octopus

January 5, 2012 • 9:31 am

I have never heard of an animal mimic mimicking yet another animal mimic, but that’s what a new paper in Coral Reefs (reference and free link below) describes.

I’ve written before about the mimic octopus (Thaumoctopus mimicus), which has extraordinary abilities to alter both its color and its shape (see video at link above) to mimic not only its background, but also other species like lionfish, sea snakes, and soles, all of which are poisonous and all of which have an “aposematic” (warning) pattern of stripes.

Predators have hence learned to avoid this pattern, which then forms the basis for the evolution of “Batesian mimicry” by the octopus. (In that form of mimicry, a palatable animal evolves a pattern resembling that of a distasteful or dangerous species so as to gain protection from predators who have learned to associate the aposematic pattern with foulness and so avoid it.  The black-and-orange striped pattern of “hornet moths” is an example.). As a potential predator of hornets (many of you have swatted them, I bet), you would certainly shy away from this harmless moth, a Batesian mimic:

Hornet Moth Sesia apiformis (Clerck, 1759). This one's found in England.

Now, however, we have a new form of mimicry in which a palatable species imitates and associates with another palatable species. Here’s from the short, one-page paper:

The Mimic Octopus (Thaumoctopus mimicus) is a remarkable imitator, apparently assuming shape and behaviour similar to models as diverse as poisonous Lionfish, Soles and Sea Snakes (Norman et al. 2001). All of those models share in common stripped brown and beige or black and white colour patterns. During a diving trip to the Lembeh Strait (North Sulawesi, Indonesia) in July of 2011, the third author filmed a Mimic Octopus for about 15 min and recorded an unexpected relationship: the Black-Marble Jawfish (Stalix cf. histrio) followed the Mimic Octopus for several minutes, remaining very close to the octopus’ arms. . . The colour of the Jawfish matched the banded pattern and colour tone of the octopus.

The jawfish is apparently a weak swimmer, and uses the octopus as a cover, apparently to move around more freely.  In some areas, though, the jawfish occurs without the octopus, so the authors regard this as a case of “opportunistic mimicry”.  It would be interesting to see (this isn’t mentioned in the article) whether the jawfish’s pattern has changed in areas where its range overlaps the octopus, which would indicate that some of that mimicry is based on evolutionary change in the fish rather than its just learning (or evolving) to behave in such a way that takes advantage of its pre-evolved pattern.

At any rate, here’s the video of the behavior. The jawfish (initially highlighted in the circle) is remarkably camouflaged.

And here’s the Black-Marble jawfish:

h/t: Matthew Cobb


Rocha, L. A., R. Ross, and G. Kopp.  2012. Opportunistic mimicry by a jawfish. Coral Reefs. Online: DOI: 10.1007/s00338-011-0855-y (free at the link).

34 thoughts on “Fish mimics a mimic octopus

    1. Because the jawfish is not an animal that is poisonous or otherwise dangerous to the potential predators the octopus faces, therefore there wouldn’t be any selective pressure favoring the octopus mimicking the jawfish.

      1. Sorry — guess I wasn’t clear.

        We know the octopus is mimicking the dangerous animals, and I would agree that there’s no reason to think that the octopus is mimicking the jawfish.

        And it also seems clear that the jawfish is mimicking something.

        But is the jawfish mimicking the octopus, or is the jawfish mimicking the original dangerous animals? Is it a first- or second-genration copycat?

        And how do we know?


        1. That’s a bit more convoluted.

          I’d guess it was the jawfish mimicking the octopus mimicking something rather than trying to mimic the other critter simply because many of the things that the mimic octopus mimics are predators that are likely to prey on the jawfish.

    2. Because we observe it trying to blend in with the octopus, and not with those other animals. (Which, as pointed out below, is not mimicry but camouflage.)

      1. Yes, but what about when the jawfish is nowhere near an octopus? Do predators avoid it as they might avoid “regular” mimics?

        Alternatively, are there any features unique to the octopus that the jawfish is mimicking, or could all of the jawfish’s features be explained by mimicking the original animals?


        1. My reading of the paper is that when there’s no octopus around, the jawfish stays near its burrow and hides from predators. There’s no evidence to suggest that the jawfish cares about mimicking anything other than the octopus. Why complicate the explanation unnecessarily by bringing other animals into it?

    1. I agree. The jawfish isn’t hoping to be noticed and avoided as something dangerous; it’s trying to avoid being noticed as it follows the octopus around.

      My question is: does it gain anything other than camouflage (e.g. food scraps) by hanging near the octopus?

      Also, it has to be said: “stripped” instead of “striped” in a professional science journal? Seriously?

    2. I don’t think there is much of a distinction between mimicry and camouflage. They’re very similar.

      But I get that there is a qualitative difference between what the octopus is doing and what the fish is doing.

      1. Camouflage usually gets applied only to specific forms of mimicry where the animal is hard to distinguish from the background, either by breaking up its outline via coloration or by having a shape similar to that of a rock or plant. From a technical standpoint, the jawfish is camouflaging itself as part of an animal that’s using Batesian mimicry.

        1. Although I suppose one could argue that, at least in this video, the octopus isn’t actually using its mimicry. It’s just ambling along in its normal octopus identity, and the jawfish is camouflaging against that.

          So I’m not sure this really counts as second-order mimicry in the sense that the selection pressures on the jawfish don’t really care why the octopus is the color it is; that’s up to the octopus genes to sort out. All the jawfish genes care about is taking advantage of this convenient moving background, i.e. pure camouflage, without any Batesian motive on the part of the fish.

          But perhaps that’s splitting hairs a bit too finely. Either way, it’s still an interesting case.

        2. That’s what I thought too — the jawfish really isn’t mimicing the octopus, it looks nothing like an octopus, unlike the moth example above. This is more like a beetle hiding in a plant of the same color, or some similar phenomenon.

  1. Is the jawfish depending on the fact that if a preditor attacks they will only center on the big yummy octopus giving the jawfish the chance to escape unnoticed?

  2. What does the jawfish do if the octopus, as they so often do, suddenly turns into something else? The octopus can change colour but the I assume the jawfish can’t.

  3. You wrote, ” As a potential predator of hornets (many of you have swatted them, I bet), you would certainly shy away from this harmless moth, a Batesian mimic.” Are you saying that the moth is a potential predator of hornets? Or is it that we (humans) are potential predators of hornets (swatting them)? And if it’s the latter, we wouldn’t we swat the moth the same way we swat at hornets? Or did you mean something like “victim” instead of “predator?” Obviously, I’m a little confused by this sentence. Am I missing something?

    1. Hornets, thanks to their venomous sting and aggressive reaction to threats, are considered to be dangerous and are generally avoided by many animals.

      Because the moth looks similar to a hornet, it is likely to get mistaken for one. This means that animals that would otherwise pose a threat to it (by trying to eat it or stepping on it) are instead more likely to leave it alone.

      Mimicry doesn’t even have to be perfect- simply generating a false identification as something that’s dangerous or uninteresting at least some of the time benefits an animal, and natural selection will tend to push the species towards a stronger resemblance towards whatever is being mimicked by way of the less successful mimics being subject to greater predation than the more successful mimics.

      1. Yes, I was unclear, but Microraptor did my job for me. We’ve learned to avoid hornets by either learning to avoid them or by being stung by trying to swat them. Hence we learn to avoid anything that looks like a hornet.

        1. Thanks for the reply. I understand how mimicry works, I just wasn’t sure who or what the “predator” was in that sentence. And those videos are great. Next time I go scuba diving I will be looking much more closely for camouflaged critters.

  4. With regard to the hornet moth and similar users of Batesian mimicry, I wonder how accurate a mimic will become before his or her potential mates will attempt to mate with a member of the dangerous species being copied… Has this even been known to happen?

    1. There are some animals and plants that mimic another animal in an attempt to fool the mimicked species into mating with them- the orchid with the wasp-like structure in its flowers or the species of fireflies that try to lure in males of a different species to eat them, so I wouldn’t be at all surprised if the phenomenon occasionally happened in reverse.

  5. The bahaviour of the fish in the video clip looks to me as though the fish is actually camouflaging itself (rather successfully)and thereby seeking to escape notice from potential predators. That would not really be Batesian mimicry which involves false advertisement with warning colours and thereby becoming more not less conspicuous).
    However it is commented that the fish also occurs in some areas without the octopus and it is possible that its colouring in these areas performs a warning function based on mimicry of other dangerous species. It would be intersting to know – perhpas from aquarium experiments – whether potential predators of the jawfish show any avoidance of it.
    A fascinating bit of film in any case.

  6. Regarding the hornet moth: That is a Great Picture! And in color, yet! Didn’t think they could do that in 1759.


  7. I’d like to ask how often his has been observed? The once between one octopus and one fish, or is it much more widespread?

    More data needed.

  8. When the novel A Scanner Darkly (1977) was made into a movie (2006) set “seven years from now” in Anaheim, California, the dialog added a reference to Catch Me If You Can (2002):

    ERNIE LUCKMAN: So this guy’s been going around claiming to be a world-famous impostor, right? Says he’s posed — at one time or another — as a surgeon at John Hopkins [sic] — as a theoretical, sub-molecular, high-velocity particle research physicist on a federal grant at Harvard — as a Finnish novelist who won the Nobel Prize for literature — as a deposed Argentinian president who was married to a go-go dancer from Chicago —

    AGENT FRED / BOB ARCTOR: He got away with all that? He was never caught?

    ERNIE LUCKMAN: OK, you broke my flow, so now I guess I’ll just have to segue to the end. That’s just it. You see, he didn’t pose as any of those. He just posed as a world-famous impostor. Yeah. It came out later in the LA Times. They checked up, and he was pushing a broom at Disneyland or something. He saw that old DiCaprio movie — you know, the one where he plays a world-famous impostor, before Leonardo hit his [fat] Elvis stage. And his first thought was: “Hey, I could pose as all those exotic guys and get away with it.” But then his next thought was, “Hell, why bother? I could just pose as an impostor and it’d be a lot easier.” They say that he made more money than the actual impostor, although I’m not sure if they’d adjust for inflation.

    1. So in real life (now), we can wonder, who made more money, Frank Abagnale, Jr. (the famous impostor) or Leonardo DiCaprio (playing the impostor)? Abagnale reportedly made $2.5 million; I imagine DeCaprio made more (but no, I’m not adjusting for inflation).

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