Recently I have been browsing theoretical alien designs and a feature I have become interested in are multiple jaws.

What I mean by this is an inner jaw located inside of the outer jaw. An example of this can be seen below (by artist abiogenisis)

enter image description here

Is it possible for an animal to have a mouth inside of their mouth?

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    $\begingroup$ Considering 3 nearly identical answers within minutes of posting, I’d call this insufficiently researched. $\endgroup$
    – JDługosz
    Sep 3, 2016 at 1:42
  • $\begingroup$ @JDługosz I had researched this, but the Moray Eel never came up. $\endgroup$
    – TrEs-2b
    Sep 3, 2016 at 1:50
  • $\begingroup$ That’s just the example picture in Wikipedia. goldfish, loaches, and many other fish have them. HDE included a link in his answer, and I linked the picture directly to wikimedia commons and didn't copy it to imager, so you can find that url. $\endgroup$
    – JDługosz
    Sep 3, 2016 at 1:51
  • $\begingroup$ @JDługosz Huh, I never knew this, thanks for this knowledge $\endgroup$
    – TrEs-2b
    Sep 3, 2016 at 1:53
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    $\begingroup$ I actually can't see the second mouth?Jaw? in the alien picture. Where is it? Anyway I wonder whether a creature could have like 4-7 jaws/mouths inside each other like a Russian doll and what it might have been used for. $\endgroup$
    – Skye
    Sep 3, 2016 at 7:37

2 Answers 2


Look no further than the moray eel.

enter image description here

While most other fish have pharyngeal jaws, those from the moray are highly mobile, probably as a turnaround to the problem that they can't chew. The oral jaw snatches the prey, but the pharyngeal jaw drags it to the eel's gullet.


That is a real thing. Many families of fish have pharyngeal jaws, some very prominant like Alien.



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