4. A Small Hole Near the Ear
In the US and UK, a tiny fraction — 0.1% to 0.9% — of babies are born with what’s known as a preauricular pit, an incredibly rare body feature. It may sound funny, but some evolutionary biologists theorized it was a gill at one point.
According to the Children’s Hospital of Philadelphia, the pit is “a sinus tract traveling under the skin that shouldn’t be there; it can be seen as a tiny opening above the ear canal and in front of the ear.”
Preauricular pits aren’t associated with hearing issues and are only rarely related to a genetic syndrome involving other problems. However, this rare body feature can be prone to infections and cysts. In such cases, the pit can be removed to avoid recurring problems.