Fish mimics octopus that mimics fish

By Ed Yong | January 5, 2012 6:24 am

Many animals defend themselves by mimicking something distasteful, like a wasp or a venomous snake. But the mimic octopus can don a multitude of disguises. It becomes a sea-snake by pushing six arms down a hole and waving the other two around in a sinuous wriggle. It turns into a flatfish by folding its arms back into a leaf shape and undulating them up and down. Its repertoire of venomous animals potentially includes lionfish, sea anemones, jellyfish, and more. It is one of the most dynamic mimics in the animal kingdom.

And now, the mimic has been mimicked.

Last July, while diving in Indonesian waters, Godehard Kopp saw a black-marble jawfish hanging around a mimic octopus. The little fish perfectly matched the octopus in both colour and pattern, blending in among the brown and white stripes of its arms.

Kopp send his video to Rich Ross and Luiz Rocha of the California Academy of Sciences, who identified the fish. Jawfish spend most of their time in burrows. Out in the open, their poor swimming abilities leave them vulnerable to predators. The mimic octopus has no such problems. Its acts are so convincing that it is relatively safe from attack. By blending in with the octopus, the jawfish seems to have found a good way of moving about openly. Octopuses are predators in their own right, but this one certainly didn’t seem to mind its fishy companion.

This relationship is probably a rare occurrence. The black-marble jawfish is found throughout the Pacific from Japan to Australia, while the mimic octopus only hangs around Indonesia and Malaysia. For most of its range, the jawfish has no octopuses to hide against. Instead, Ross and Rocha think that this particular fish is engaging in “opportunistic mimicry”, taking advantage of a rare chance to share in an octopus’s protection.

Reference: Rocha, Ross & Kopp. 2011. Opportunistic mimicry by a Jawfish. Coral Reefs. http://dx.doi.org/10.1007/s00338-011-0855-y

Images from the authors.

Hat-tip to Cameron Turner for alerting me to the story

More on mimicry:

Comments (4)

  1. Cool video and a fascinating bit of natural history. But unlike the authors, I don’t think my first inclination would be to call this relationship “mimicry.” The fish is difficult to detect against the brown-and-white mottled pattern of the octopus; it’s not fooling any predators into thinking it *is* an octopus. More like an excellent example of crypsis. But it’s certainly an interesting form of crypsis, wherein the visual background is another living, motile organism. (Are there any other examples like this? I don’t know.)

  2. Danny Byrd

    It is clear that in December 2012 they will hit the mimic singularity.

  3. @Neil – That’s true! It’s one of those odd behaviours where our terminology suddenly seems a bit lacking.

    @Danny – I give you this: http://xkcd.com/928/

  4. Daniel J. Andrews

    Springerlink seems to be not working at the moment so can’t read the paper. My initial thoughts were the same as Neil’s. This seems to be more an example of crypsis rather than mimicry….but perhaps the authors have addressed this issue. I’ll try from work tomorrow.

    Certainly though, this is a fascinating example in its own right.

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