Why Do We Have Eyebrows? What Are Eyebrows For?

Why Do We Have Eyebrows? What Are Eyebrows For?

Why do we have eyebrows? What are eyebrows for, and what purpose do eyebrows serve? We’ll explore these questions and more in this blog post.

Human Body Hair

Remember the days when humans resembled Cousin Itt from the Addams Family? Well, of course you don’t, but humans of the past were quite hairy. As the centuries progressed, however, our body hair became less and less. We used to require this excessive body hair in order to keep us warm in extremely cold and harsh environments. However, warmer climates mixed with inventions like housing, indoor heating, and sufficient clothing, meant that humans evolved to no longer need all that extra insulation. In fact, that same level of heat actually became a hazard to us and our health.

The more hair you have the less you are able to sweat. Sweating is an important human function because it helps the body cool off faster. This became crucial when our prehistoric ancestors began to travel on two legs, and fast. If those early humans began to overheat, it could have potentially jeopardized the health and growth of their brains. And this would have certainly prevented us from becoming such an intelligent species.

So the amount of hair we had started decreasing generation after generation, and soon we were the nearly hairless (by comparison) creatures that we are today. That is, except, for a few parts of body—like our eyebrows. So the question remains, why do we have eyebrows?

Why Do We Have Eyebrows?

One of the simple answers for why we have eyebrows is because they help us fight off sweat. Have you ever noticed that one of the first areas to gather sweat when you begin to do anything physical is your forehead? Well, this can be extremely inconvenient because in case you haven’t noticed, your sweat has a pretty high salt content. When sweat gets in your eyes it can be quite uncomfortable, and it can make things hard to see.

Thanks to your eyebrows, however, sweat has a tougher time reaching your eyes. The patches of hair allow moisture to be collected and held back. What’s more, the outward direction in which your eyebrows grow helps to angle the sweat towards the sides of your face rather than letting it stream straight down. In a way, having eyebrows is like wearing a permanent partial headband.

The second important reason for our continued possession of eyebrows is to convey proper facial expressions. As studies like this 2003 facial recognition test have shown, eyebrows are extremely important in the ongoing demonstration of emotions and facial familiarity. Without them, you would not be able to easily convey skepticism or anger, as your eyebrows would not be there to properly adjust. You would also be less recognizable to your friends and family without your eyebrows, even more so than if you covered your eyes.

So to sum up the reason for these seemingly pointless genetic remnants, eyebrows keep moisture out of your eyes and help you express emotions. You may be tempted to pluck and wax away your eyebrows, but as it turns out, there is a very good reason why they are there.

If you liked this post, you might enjoy these other anatomy articles from the Sporcle Blog.

Or if you want to test your trivia knowledge, try some fun anatomy quizzes on Sporcle.com. You can start with the quiz below!