The Strange Reason We Have Hair On Our Butts

Minus our lips, palms, and bottoms of our feet, the entirety of our body is covered in hair. At first glance, reasons for hair growth might seem more logical in certain areas of the body than others. Take scalp hair, for instance, which research shows may have served an evolutionary purpose of preserving body heat while also protecting against the effects of solar radiation (via The Proceedings of the National Academy of Sciences). Hair growth inside the nose also makes sense, as these tiny hairs prevent contaminants from entering the body through the nostrils. What's not so obvious, however, is what purpose a hairy derrière could possibly serve.

Like many of our physical traits, there may be a genetic component at play if you have an abundance of hair on your buttocks. If one, or both, of your parents has a hairy butt, this will likely influence the color or thickness of the hair on your rear end. While this may seem like a more obvious reason as to why one might have hair on their butt, there's another, slightly more strange reason as to why we may have hair on our butts — or more specifically, between our buttocks.

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.

Sometimes, hair growth on or between the buttocks may be related to a health condition or the use of certain medications, explains Healthline. Having overactive adrenal glands, polycystic ovarian syndrome (PCOS), or hirsutism are all conditions that impact hormone function and may boost body hair growth. A rare condition known as "hypertrichosis" may do the same. Although there are different types of hypertrichosis, "StatPearls" outlines how the condition is characterized by an excess of hair growth that occurs anywhere on the body. In cases of congenital generalized hypertrichosis, genetic abnormalities cause developmental issues within the hair follicles. In cases of acquired generalized hypertrichosis, however, the cause can often be traced to medication use. Such medications may include certain antibiotics, diuretics, anticonvulsants, vasodilators, or corticosteroids.

For aesthetic purposes, some people prefer to have their butt hair removed. When done safely, shaving, waxing, electrolysis, or laser hair removal can be effective options. However, epilator devices and depilatory creams should be avoided at all costs, as these can cause pain or discomfort in this particularly sensitive area.