Fevers are uncomfortable, annoying and occasionally dangerous. But they are also an essential part of how we protect ourselves.

It's 3am and you can't sleep. Sweats and shivers let you know something is not quite right. A furnace-like heat races to your forehead, shivers and chills trickle down your spine. You feel helpless, confused and exhausted. "It's only a fever," you tell yourself.

An evolutionary feature  by Sarah Pitt.)