I'm designing a creature which possesses a decently unusual trait: despite having a developed head, it's mouthparts are attached to a tentacle that retracts into the creature's belly when not in use, similar to a flatworm, but with a more elaborate structure and complex mouthparts at the end of it. Based on this, Could a creature evolve to have a mouth separated from it's head?

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  • $\begingroup$ What exactly are you looking for? Is it for your creature to be able to extend its pharynx beyond the mouth? $\endgroup$ Apr 23, 2020 at 19:54
  • $\begingroup$ I'm asking about a complex creature where the mouth is on the end of a tentacle attached to the creature's torso $\endgroup$ Apr 23, 2020 at 19:59
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    $\begingroup$ Then you should try and edit the question to make it more clear what exactly you want. I recommend to avoid the use of "how" in your questions whenever possible, as the aren't usually well seen (make the question seem too broad). Also, I recommend taking a look at squids ( how to have a hard beak in a soft body) and goblin sharks (Jaws that can extend forward) $\endgroup$ Apr 23, 2020 at 20:05
  • $\begingroup$ I'll ask you to give more details about your creature in your question (what it eats, if it's a skeleton, body, number of limbs etc) so that the question can have more details. $\endgroup$ Apr 24, 2020 at 0:55

2 Answers 2


If you have a body plan without a head, you can put the digestive apparatus where it makes the most sense.

starfish feeding


A problem is how "head" is defined for us - we think of heads like the familiar tetrapods have. A system with a feeding orifice separate from the "head" makes more sense as you get farther away from a body plan with a conventional head. We are used to having a lot of important stuff all piled into the head but there are successful body plans from different phyla that do it differently. Starfish have sensory organs on the tentacles and a more distributed means of locomotion (tiny feet), so it does not seem so unusual that their central "pharynx" (really an evertable stomach) is in another different place.

Moving digestion away from sensation, locomotion etc makes sense. But I struggle to think of a system where the digestive apparatus is decentralized - for example entirely in one (or more) appendages. Probably because digestion is so central to a creature that lives this way, and also resource intensive to maintain.


Yes. For similar reasons as Turtles have their necks the way they have it. The reason why they woud evolve it like that will probably be protection of the pharynx.


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