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

To put it simply, they have adapted to be able to subsist on that diet. More specifically, the gut microbe in herbivores help break down that tough plant material. From there the animal can derive all their energy needs, and they can synthesize what they can’t get from the plants. We humans for example, usually consume some form of meat. That’s because some amino acids and vitamins are less prevalent in plants, and we can’t synthesize them by ourselves.