Eyebrows are the two strips of hair that grow on the top ridge of each eye socket, framing the brow and preventing dirt and sweat from contaminating the eyes. The average eyebrow is thought to consist of around 500 single hair-follicles.

Many experts believe that our eyebrows are the last remnants of a far hairier past, at a time when our distant ancestors were covered head to foot in fur for warmth and protection – much like modern apes are today. However, millions of years of evolution meant humans gradually lost their natural covering and took to stealing other animals’ coats instead, giving rise to us: ‘the naked apes’. So the interesting question is this – why did we lose all of that hair and yet still keep our eyebrows?

Some experts believe our eyebrows do more than simply keep dirt out of our eyes.