Scientists are saying that the reason some people are born with a tiny hole above their ears may have something to do with the evolution of fish gills.
The condition is called preauricular sinus. Less than 1 percent of people in the U.K. are born with it, and the number is even lower for people in the U.S., the Daily Mirror reported.
In parts of Africa and Asia, anywhere from 4 to 10 percent of people are born with preauricular sinus.
The birth defect features "nodules, dents, or dimples" anywhere in the area of the external ear -- more frequently where the face and cartilage meet.
Preauricular sinus is largely considered a hereditary birth defect. It was first documented in 1864 by scientist Van Heusinger. The tiny holes can be found near one ear or both, but appear more frequently on the right ear.
What's more interesting is what the tiny holes could signify.
According to evolutionary biologist Neil Shubin, the holes could be an "evolutionary remnant of fish gills," Business Insider reported.
The condition could also be linked to other factors, and rarely causes problems. The holes can become infected, but can easily be treated with antibiotics. In extreme cases, surgery could be required to remove the sinus entirely.
Putting jewelry inside the sinus is also strongly discouraged.