Humans evolved to live on an icy planet. Earth is usually much hotter.
As Earth approaches warmer levels experienced earlier in its geologic history, it may be bad news for human survival.
Harvard Scientists Just Discovered Why Humans Burn Energy Like No Other Animal
Humans have evolved an exceptionally high metabolic rate, unlike any other known animal. Unlike primates that conserve energy by being less active, humans can stay on the move thanks to sweating, ...