Does having more stomachs make digestion more efficient?
Depens on what you try to digest. Cows and other ruminants have several stomachs, because their main diet contains lot of cellulose. Vertebrates do not have enzymes to digest cellulose, so there has evolved symbiosis with cellulose digesting bacteria. Some animals, like rodents, gorillas, birds, have huge appendixes containing these bacteria and they also have very long small intestine to help absorb as much as possible from the food. Some also eat their extrements to digest left over nutrients. Ruminants have separate stomach to keep the bacteria in. grass-eating non ruminants,which do not have huge appendixes like horses for example have efficiently two stomachs for the same purpose (they have one stomach, but it is kind of used as two – there are two food masses, which are kept separate by muscles) Same systems, different ways to do it. Answer to your question – yes, several stomachs are there to help digestion. Humans would also benefit from ability to process cellulose, I think.
