Let's start with the first breakthrough when it came to human fashion: We lost our fur. Sure, bare skin is all the rage these days, but it wasn't always the style. Researchers now suggest that humans might have developed a less Robin Williams-type look around a million years ago. They propose that early humans were at risk of overheating their brain if they couldn't cool their skin by sweating, a trick that's a lot easier when you're not dealing with tangled, dense fur [source: Connor].
Once we lost our body sweaters, however, we faced a greater risk of exposure to the elements, so we had to put on some clothes. It's hard to determine exactly when humans started wearing coverings; animal pelts don't make good artifacts because they decompose [source: Upton]. (Not to mention that hides were used for shelter and other uses besides clothing.)
So researchers at the University of Florida did something pretty cool. They decided to see when clothing lice split genetically from head lice [source: Toups et al.]. (Did you even know the two were different?) Turns out that 83,000 to 170,000 years ago -- just around an ice age -- clothing lice came into existence, as did, researchers assume, clothes. So for hundreds of thousands of years, we did have a ball running around naked. But clothes, whether pelt or pashmina, have literally saved our lives innumerable times since then [source: Viegas].