I had an idea few years back for a species of "cow" living in arctic/tundra climate which could forage on "anything"- in their habitat it would be mostly vegetation, wood and remains of dead animals including bones. Clay or small rocks should work too if they include some useful minerals. They would be domesticated and fed any waste the humans would produce. They would probably be very strong, but slow, with slow metabolism similar to a sloth. These traits aren't absolutely necessary though. My question is, is it possible (and viable) to have digestive system capable of digesting almost everything? If it can exist, what effect would it have on animals biology and behavior? Some magic can be included but I would like to avoid that. The animal doesn't have to evolve naturally, but it has to be able to survive for many generations.

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    $\begingroup$ Sounds like a goat/pig hybrid. Goats eat almost anything plantlike and pigs have no problem with waste and Meat, dead or alive as the chickens of a friend found out. $\endgroup$
    – Demigan
    Dec 28, 2018 at 12:44
  • $\begingroup$ Control the hydrogen ions level and make sure to coat stomach wall with teflon, moooooo $\endgroup$
    – user6760
    Dec 28, 2018 at 13:48
  • $\begingroup$ I really can't see why this is being VTCed as duplicate. That other question (closed, by the way) asks about some "thing" (not even an animal per se, according to the OP) that consumes planets. The present question is restricted to ordinary planetary biology and animal physiology. Leave Open $\endgroup$
    – elemtilas
    Dec 28, 2018 at 16:02
  • $\begingroup$ @elemtilas, I retracted my vote (VTR), but the size of the creature doesn't change the nature of the question - and the two questions have intrinsically the same condition: creatures that can eat anything. Nevertheless, the OP is basically describing a goat the shape of a cow. Why is the biology and behavior of a goat not satisfactory? $\endgroup$
    – JBH
    Dec 28, 2018 at 16:42
  • $\begingroup$ @JBH -- fair enough about size. But the nature of the original question -- it could be an animal, it could be a machine -- I think does change the nature. No animal, properly understood, could consume and digest material from a planetary core. That's solid nickel-iron that's hotter than the Sun and under incredible pressure. Talk about indigestion! The present question also limits the meaning of "anything" (note the quote!) to articles found at the surface: vegetation, carrion, minerals. Re goats: looks like a good answer to me! $\endgroup$
    – elemtilas
    Dec 28, 2018 at 17:06

3 Answers 3


It's not entirely unreasonable. Largely because that's how it currently works.

Most true herbivore digestive systems are keyed to a herbivorous diet, but where there diet is unable to provide all the nutrients necessary, they will diversify. Mineral mud is not uncommon where diets can't provide certain elements, some also consume specific minerals to act to neutralise the poisons in their diet. Even at a very basic level, a salt lick is a normal feature in a horse's stable. Elephants will eat twigs and branches in extremis, though it's not a good diet for long or for the young.

As for meat, cows have been recorded to occasionally eat birds or other animals of their own accord (domestic animals often have animal produce in their feed).

So your average cow may well have a diet as you request, mostly grass, some rock minerals, some meat, some whatever.

  • $\begingroup$ Agreed. OP wants an ox. $\endgroup$
    – Willk
    Dec 28, 2018 at 13:02

If you give it a strong stomach filled with H₂SO₄ this should be enough. Well some of it could end up out of the intestinal tract. Also making the crap pretty dangerous. This species could survive but they need a very strong body, with high acid resistance.


As you know, cows already have multiple stomachs. As has been pointed out they can eat animal products (and indeed this was the reason for mad-cow disease - not the fact they were eating meat but because they were eating the brain and other nervous tissue of infected animals).

For tougher materials including glass and stone etc. a gizzard is necessary. By eating pebbles and storing them in the gizzard, hard substances can be worn down to a finer consistency.

The gizzard, also referred to as the ventriculus, gastric mill, and gigerium, is an organ found in the digestive tract of some animals, including archosaurs (pterosaurs, crocodiles, alligators, and dinosaurs, including birds), earthworms, some gastropods, some fish, and some crustaceans. This specialized stomach constructed of thick muscular walls is used for grinding up food, often aided by particles of stone or grit. https://en.wikipedia.org/wiki/Gizzard


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