I heard some guy say that we can't digest plant food as well as herbivores. Which seems weird to me seeing as how humans can survive without any nutrient deficiencies besides b12 on only plants but we would pretty much just die of nutrient deficiencies on a carnivore diet. Can someone show me how we can't digest plant food as well as herbivores?

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    $\begingroup$ Hi and welcome to Bio.SE! This is an interesting question, but it remains quite broad at the moment. Could you narrow down which plant food you mean. For example, we can eat onions but they are somewhat toxic to horses, yet most grasses would probably cause us to vomit whilst cows can't get enough of the stuff! More context is key to making this an answerable question. $\endgroup$
    – James
    Nov 9, 2016 at 3:25

1 Answer 1


Humans do not have microflora that can hydrolyze cellulose, but plant-eating herbivores do. One advantage of that though is that the cellulose helps move food through your gut and aids digestion. Herbivores have fermentation chambers in their alimentary canals that contain mutualistic bacteria and protists that can break down the cellulose for them; some of the microorganisms also use some of the sugars from the digested cellulose to produce nutrients vital to the animal, such as vitamins and amino acids. Also, herbivores have longer alimentary canals relative to their body size, due to the fact that plant matter is harder to digest because of the cell walls.

Here is an excerpt on herbivore teeth structure, taken from Campbell Biology, 10th Edition.

"Herbivores, such as horse and deer, usually have premolars and molars with broad ridged surfaces that grind through tough plant material. The incisors and canines are generally modified for biting off pieces of vegetation. In some herbivores, canines are absent" (Reece et al. 906).


  1. Reece, Urry, Cain, Wasserman, Minorsky, and Jackson. Campbell Biology. 10th ed. N.p.: Pearson, 2014. Print.

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