Our outer ears may have come from ancient fish gills, scientists discover

On the left, a fish with its mouth open and gills visible. On the right, a person holding their outer ear out.

Humans' outer ears may have evolved from the gills of prehistoric fish, a new study finds.

Gene-editing experiments indicate that cartilage in fish gills migrated into the ear canal millions of years ago during the course of our evolution. Going even further back, our outer ears may have evolutionary roots in ancient marine invertebrates, such as horseshoe crabs, scientists say.