Eli5: how are humans, who are two legged, able to out endure creatures that are four legged?

Question

Eli5: how are humans, who are two legged, able to out endure creatures that are four legged?

In: 1455

Answer 1

It’s because most animals are completely incapable of running in an aerobic state, which allows us to fuel our muscles with the oxygen we breathe, so we don’t run out of energy. When we sprint (and the only way most animals can run), it’s anaerobic, which uses energy stored in the muscles, and there’s a finite reserve of those.

Imagine an ultra long distance race between a slower solar powered dune buggy and a faster gas guzzler. Eventually the car will run out of gas and the dune buggy will catch up. Then it’s game over.