It's a question that's confounded generations of scientists and brilliant thinkers: Why do we have hair in our butt cracks?
Finally, we have some answers. According to a YouTube video posted by SciShow, we likely have butt hair because there's "no significant evolutionary pressure against butt hair." Basically, we still have it just because we can.
In the video, host Hank Green reminds us "not every bit of our physiology needs an evolutionary purpose." So, it's basically just evolution being lazy that leaves us with unnecessary hair in our cracks.
Another, much grosser theory is we need our hair to keep our butts smelly and all the better for sniffing. Seriously, if it works as a communication tool for dogs, it could surely have worked for our primitive ancestors at some point.
The third theory has to do with chafing and anal pelage, so I'm just going to let you discover that one on your own.
Watch the video above for the full scientific breakdown of why we have butt hair.