As a thought project, I wanted to make an alien species that eats without any use of the tongue, but I've run into the problem that it's almost impossible to swallow solids without choking without the manuverability/vacuum the tongue provides. However, I stubbornly believe a tongue is not needed to eat for a jawed vertebrate with the following restrictions:

  • The alien has a jaw configeration similar to most jawed vertebrates (think dogs, not snakes; the jaw is not split and cannot move independently to walk food down the esophagus like snakes do)

  • The alien has bifurcated lips that can move independently of eachother; imagine if you could move your upper and bottom lip as freely as your fingers, but they had a division down the middle where your cupid's bow is (providing more moving parts for extra dexterity)

  • The alien chews it's food minimally in the mouth, then it gets sent to the crop/gizzard for further pulverization, then back to the mouth until it is adequately chewed.

The alien CANNOT

  • Possess a secondary jaw (although a dexterous, prolapsing esophagus would be okay)

  • Have an open jaw matrix like invertebrates/insects with external manipulators

But the alien MAY

  • Seal off it's airway while eating or otherwise have an unintegrated airway to the esophagus (In other words the airway does not go anywhere near the mouth)

  • Have a wacky esophagus (such as being able to close, prolapse, or tighten in select areas and not others)

Or any other solution that isn't flat out having a tongue or defying any of the restrictions I've put in place.

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    $\begingroup$ You know there are humans born without a tongue and they swallow food just fine, right? I've personally met one. There is some disinformation in the internet saying there are only a couple handful people in the world with congenital aglossia but I believe this number is actually a gross underestimation. $\endgroup$ – The Square-Cube Law Feb 12 '20 at 5:40
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    $\begingroup$ Snakes have tongues but I'm pretty sure they don't use them to swallow with $\endgroup$ – cyber101 Feb 12 '20 at 5:53
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    $\begingroup$ @cyber101 Snakes shuffle food into their throats with their divided lower jaw bones, they quite literally walk the food into their mouths. One of the restrictions I put is that my alien cannot do that. $\endgroup$ – Tardigreat Feb 12 '20 at 5:54
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    $\begingroup$ It is worth mentioning that humans are especially prone to choking, even compared to most mammals, because of a quirk in the way our larynx is positioned (the same quirk that allows us to speak) and the way our lungs are joined to our esophagus. It would be trivial for an alien species to have a different arrangement. Whales, for instance, have no direct connection between their breathing-holes (blowholes, which are actually their nose) and their feeding-holes, so they cannot choke while swallowing food. (They can choke if things get stuck in their blowholes, but that is unrelated). $\endgroup$ – IndigoFenix Feb 12 '20 at 8:52
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    $\begingroup$ @LiJun it is true it does not get much use in swallowing it has a much more important function as a water tight valve, and due to the size of what they eat it can't help much but it does function what throws most people off is the tongue does not fill the mouth like many animals. it only starts at the back of the jaw. the front half or more of the jaw is tongueless. but it is fully formed at the most important section the throat and esophagus. $\endgroup$ – John Apr 28 '20 at 3:17

Different swallowing techniques:

  • Strong throat muscles: Once getting food between the jaws, stick your neck up allowing gravity to throw your food into your gullet, at which point the throat muscles take action and crush the food for you. No tongue!
  • Sublimation: I don't think this exists on Earth, but acids inside the creature's mouth turn the food into a gas or liquid, allowing it flow into its unique digestive system. Can also be used as a weapon against enemies (via spit or bite). May violate your 3rd bullet-point though.
  • Lip-Slingshot: You mentioned bifurcated lips - any chance the animal can kind slingshot food into its throat by using the elasticity of its lips? Messy eater though.
  • Starfish: I know you said the secondary jaw was not an option, but what if the creature's stomach traveled up to its throat? Not exactly like starfish, as some species eat with their stomachs directly, but kind of close.

I hope this helps!

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    $\begingroup$ If chewing helps imbue the acid into the food, that could work. I just don't want to totally eliminate chewing. It's possible that their saliva or upchucked gastric acid softens the food enough to liquify it, but it's vastly expedited by the grinding action of the crop and jaw similar to our stomach churning. $\endgroup$ – Tardigreat Feb 12 '20 at 6:07
  • $\begingroup$ I think flies almost count as an example of animals that do sublimation. Some carnivore plants do fit the bill. $\endgroup$ – The Square-Cube Law Feb 12 '20 at 12:27
  • $\begingroup$ @Tardigreat yeah that sounds like a good work-around - I didn't consider that possibility $\endgroup$ – cyber101 Feb 12 '20 at 14:54
  • $\begingroup$ @Renan wasn't aware of that - that's really cool! $\endgroup$ – cyber101 Feb 12 '20 at 14:54

There are several possible solutions to this if you think about it.

The tongue is used to manipulate food in your mouth. It isn't 100% there to shove it down your throat.

On example would be birds. Birds often have fairly fixed tongues. They don't usually go outside of the mouth and have small upwards and downwards movements. In this case, you can see some curious head movements and beak shapes which allow a bird to guide the food into its throat which it then swallows. A key example here would be birds like the Pelican which scoop fish out and sort of just pour it down their throat.

Second example are crocodile. Their tongue has little use. They just clamp down on their prey. Tear at the flesh. Then sort of jerk their head back until the food is in the appropriate position and swallow.

Other examples include Fish, Turtles, Hippos and people who don't have tongues. While all but one have tongues. I believe you can imagine that the tongue has a very minimal role in all these animals eating food. Gravity and body movements make a decent substitute. Alternatively, smushing your mouth with so much food it has to go down your throat is another viable method.

As an extreme example, you can look at an elephant. Instead of having a tongue, you could potentially just push the food into your throat so you can swallow it.


What if it didn't have to breath through its mouth?

One of the main functions of the tongue is to push the food into the throat, it does this so food doesn't go into our airway and we don't choke. But if your airway wasn't in your throat, there would be no risk of choking, so something getting stuck wouldn't be a big problem. Instead of having a tongue, the floor of their mouths could be inclined so when the food gets covered in saliva, it can simply slide down into the throat without assistant. Their saliva would probably need to be more acidic/basic to break down foods a bit quicker and make them more slippery. If something gets caught in its throat, it would be a nuisance, but certainly not life threatening; it could either wait for the object to break down in its throat, hack it up, or force it down.


Use fingers.

If dogs were to consider how humans eat, they would be puzzled. Our faces are so short. How can we bite up our food? The answer - except for drunk lady rugby players exploring alternatives, we move food to mouth using fingers. We put it in our mouths. We can poke it right in there should we choose.

Take that further. Poke the food all the way into the throat with the fingers. Poke it down the throat and let the esophagus take it from there. A short mouth, long fingers, powerful throat and gizzard would all help with this endeavor but it is not that wacky.


The creature could suck food down its throat. Some fish do this in reality, and it should be possible on land if the mouth can be sealed


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