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I am developing a species that gives birth to live young after a very brief pregnancy. The infants are somewhat underdeveloped due to this fact. The harsh environment of the mountains means that those who carry the infants can't survive long pregnancies due to that fact that they would have to burn substantial calories to heat themselves as well as their several young.

In response to this, they birth their young after only three months, when they are just able to regulate their body temperature well enough to survive. They spend most of their time in the womb developing, so their digestive system is much more underdeveloped at birth.

This species solves this problem by having a special pouch around their neck, where they store partially digested food for their infants.

My question is, could they still potentially use said pouch to store food for themselves. Is there a way in which the muscles of their neck would allow them to both swallow and regurgitate food from a pouch like this?

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    $\begingroup$ The proposition that infants be born early because their mothers cant get enough calories to keep them warm inside of them sounds like a losing prospect for the infants. Not to suggest pregnant women are spherical cows, but which loses heat faster - one largish spherical cow or 1 medium + 1 small spherical cow? (Hint - it is not the largish one). $\endgroup$ – Willk Dec 12 '18 at 20:06
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    $\begingroup$ Having been a non-spherical-cow pregnant woman, I can tell you that keeping a newborn warm is hard. If I lived outdoors in a wintery environment, I would have lost a lot of babies that way. Even mothers living indoors in times/places with poor heating options would have babies die from that. I'm talking about full-term infants who can regulate body temp. But when pregnant, I never worried about keeping the fetus warm. As long as I was warm enough that I didn't die, my baby was fine. $\endgroup$ – Cyn says make Monica whole Dec 12 '18 at 21:34
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    $\begingroup$ @Cyn - that last sentence sums up the mammal miracle. Generally as long as mom is [thing she needs] enough that she doesn't die, baby inside can get by too. Mom has practice getting [thing she needs] enough not to die. $\endgroup$ – Willk Dec 12 '18 at 21:51
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    $\begingroup$ @Willk of course keeping hte infant separate means if resources run short less is wasted on an infant that cannot survive. And just because it is a poor choice does not mean they might not still be stuck with it, evolution rarely produces perfect solutions, look at penguins and their eggs. $\endgroup$ – John Dec 13 '18 at 2:56
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    $\begingroup$ WRT short gestation and keeping the young in a pouch, I think you've just invented the kangaroo :-) (Or indeed, perhaps the whole class of marsupials?) But I would think that a pouch for both infant and food would not work well: too much risk of accidentally swallowing Junior. $\endgroup$ – jamesqf Dec 13 '18 at 5:53
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Absolutely! There are a number of real-world examples of something similar, including many birds as well as ruminants. Admittedly these groups don't store the food in their necks, but in principle the mechanism exists.

However, the evolutionary practicality of a food-storage pouch may be harder to show. Storing food as fat would probably be more efficient than storing the food itself. Perhaps if the pouch had a secondary function (say, housing symbiotic bacteria that metabolize food and produces a vitamin not found elsewhere in the animal's diet) the evolution for personal use would be much more plausible.

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  • $\begingroup$ Hey, there appears to be a line missing from the end of your first paragraph. $\endgroup$ – Cyn says make Monica whole Dec 12 '18 at 21:30
  • $\begingroup$ Best place to store food is to eat it. It can’t go bad then, and it is as compact as it can be for transport. Only reasons not to digest it is if it is going to be given to others or it is in such quantity that you want to be able to set it down for a while and move around without it. $\endgroup$ – SRM - Reinstate Monica Dec 12 '18 at 23:11
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    $\begingroup$ Birds actually do store food in the neck, at least the base of the neck. $\endgroup$ – John Dec 13 '18 at 3:11
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Hamsters have cheek pouches.

enter image description here

And here is a video https://youtu.be/jbYBGKSxyac


Cows chew the cud - they have various levels of stomach

Once swallowed, the food goes into the first section, the rumen, where it mixes with other acidic digestive liquids and is softened. The softened food is called cud, small balls of food.

Next, the rumen muscles send the cud back up to the cow’s mouth, where it is re-chewed and swallowed again, this time going to the Omasum section of the stomach in order to squeeze out all of the moisture.

enter image description here


Birds typically have a crop.

A crop (sometimes also called a croup or a craw, or ingluvies) is a thin-walled expanded portion of the alimentary tract used for the storage of food prior to digestion.

https://en.wikipedia.org/wiki/Crop_(anatomy)

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Birds do exactly what you're describing. The anatomical feature is called a crop.

To the best of my knowledge, birds don't tend to store partially digested food in their crops. They store undigested food, to account for a need to eat fast and limited stomach capacity. Birds do regurgitate partially digested food for their young, but that's from the stomach, not the crop.

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    $\begingroup$ some digestion does begin in the crop mostly just some enzymes to soften the food. , Doves go even further and use it to produce something akin to milk for their young. Crop milk $\endgroup$ – John Dec 13 '18 at 2:51

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