How are some of the largest land animals like Rhinos, Elephants and Giraffes are herbivores? How do they get so big from eating grass, don’t they ever get hungry?

Question

I don’t get how something so big just eats grass like a cow. If we eat vegetables all day we won’t get fat or super big so how are they able to do it? I feel like eating grass all day is not very filling.

In: Biology

Answer 1

You have cause and effect the wrong way round.

Grass and leaves are not very nutritious. It can therefore be effective to have a large and complex digestive system to extract calories from them. This necessitates a large animal.

Also an animal which eats grass has few excess calories, which means it cannot spend its life running. Being large is an effective defence mechanism for a slow moving animal.

Which leads to the question, how do sheep exist?