Squid are covered head to tail in sensory hair cells much like those inside the human ear. The discovery could open a new window into hearing loss.

Researchers at Case Western Reserve University found hundreds of previously unknown hair cells lining the entire surface of squid bodies. It is the first full-body map of squid lateral lines.

The team used light-sheet microscopy, a laser imaging technique that builds detailed 3D images without damaging tissue. Part of the work was done at the Marine Biological Laboratory in Woods Hole.

Unlike fish, whose hair bundles are uniform in length, squid tune their bundles to different frequencies. That mirrors how the human ear handles high and low pitches, the researchers said.

In humans, damaged hair bundles are a leading cause of permanent hearing loss because they cannot regenerate. “Studying the squid’s hair bundle holds promise for understanding how hearing loss occurs,” said team leader Brian McDermott.

The findings were published in Current Biology on September 21.