ELi5: How do some animals get enough nutrients out of eating hay or grass or a single variety of leaf for their entire lives?

Question

ELi5: How do some animals get enough nutrients out of eating hay or grass or a single variety of leaf for their entire lives?

In: 293

Answer 1

You’re referring to cellulose. It’s what gives plants structure. Humans cannot digest cellulose. So if we ate grass and leaves all we would get is a tummy ache. But a lot of animals can digest cellulose. Broadly speaking animals that can digest cellulose are called ruminants. They are able to digest cellulose thanks to their weird stomachs. While you and I just have one cavity in our stomach where all our food goes, ruminants have a 4 chamber stomach. This lets them digest the fuck out of whatever they’re eating. And with some help of healthy gut microbes the cellulose can be broken down into simpler carbohydrates. Which can then be digested normally.