Formal lifestyle paper

If I had four stomach chambers, I could probably extract energy from a wider variety of vegetation than I can now.

Plus I could chew cud, eliminating the expense of chewing gum.

 

Cellulose is the thing here. It is why there are elephants in the room.

Just looking at cellulose structure one might not see it as such a barrier. Yet it is, and organisms other than bacteria and fungi just can't break it. The hack is to provide a home for bacteria and/or fungi in one's digestive tract. Ruminants most famous for this but there are several other examples of teamwork like that.

Wood-boring beetles carry spores of (competent) fungi in their armpits when they fly off to a new tree.

If a human's diet is sufficiently dominated by yams (or something similar I forgot), large intestine can develop bacterial populations that assist in biochemical decomposition. There always something like that going on 'down there' but this particular arrangement leads to methane farts.

It is as close as @ChapmanF can get to rumination. Do or do not.

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Probably mentioned this before. An article published in Science (one of the top journals) has been cited by other publications a huge number of times. Really out there. It is because the author's estimate of methane from termites was waaaay too high. Those citations say "that was very wrong".

Author of first-linked publication here might actually become highly cited, by others saying "don't do like this".