Why do we get wisdom teeth?

Wisdom teeth are the third and final set of molars, usually emerging in the late teens or early twenties, the age once associated with gaining wisdom. Our early human ancestors had larger jaws and ate a coarse diet of raw plants, nuts, and tough meat that wore teeth down heavily, so a third set of grinding molars was useful. As human diets softened with cooking and food processing, and as skulls and jaws evolved to be smaller, there is often no longer enough room for these extra teeth. As a result, wisdom teeth commonly become impacted, growing at an angle or getting trapped beneath the gum, which can cause pain, infection, and crowding. This is why so many people have them surgically removed. Some people never develop wisdom teeth at all, a trait that appears to be becoming more common.