Perspiration can be a stinky nuisance as temperatures climb, but scientists say we shouldn't sell sweat short. There's so much more to the briny stuff than meets the eye.

So sweat doesn't really smell bad at all. But when bacteria eat the sweat — nostrils, look out! Only it turns out that these sweat-eating critters are responsible for a big health benefit.

Sweat is an "evolutionary marvel," says Sarah Everts, the author of The Joy of Sweat. In her new book, Everts delves into the science of perspiration and how this trait has enabled humans to thrive.