With nearly 8 million subscribers, the hosts of the SciShow YouTube channel explore viewers’ most burning scientific questions. Butt hair was the subject of one particular episode back in 2016, in which YouTuber Hank Green offered the theory that the hair between our buttocks may have helped our early ancestors find a mate. It sounds bizarre but stay with us. Green refers to this as the “scent communication” theory, explaining that butt-crack hair, much like why we have armpit hair, traps the oils from our skin. These secretions serve as a tasty snack for bacteria, which further enhances our natural scent. Our distinct aroma is unique to each of us, which may have been exactly what enticed a potential partner back in the day.
Mating aside, the hair around our anus may alternatively serve a more practical purpose. Green explains that humans are almost always in motion, and all that movement can cause a lot of rubbing between the buttcheeks. To reduce the risk of subsequent skin damage or infection, butt crack hair helps lessen the friction that takes place as we walk.
