The symbiosis between cows and the bacteria that live in their digestive systems is also interesting. These bacteria digest the cellulose found in hay and grass for the cow, while the cow offers nutrient-rich environments for the bacteria. It’s a win for both organisms. Combined with their multilayered stomach and short appendix, this relationship means cows can eat tough plant foods. Humans cannot digest cellulose in part because they do not have cellulose-digesting bacteria in their digestive systems!
