What distinctive head shape gives hammerhead sharks their name?

What distinctive head shape gives hammerhead sharks their name? A cephalofoil gives them their broad, hammer-shaped head.

The cephalofoil is a flattened structure extending sideways from the front of the shark’s skull. Its exact outline varies by species: great hammerheads have a strongly T-shaped head, scalloped hammerheads have a central notch, and smooth hammerheads have a rounded, unnotched edge.

The shape is more than a visual trademark. The widely spaced eyes provide a broad field of view, while the expanded head gives room for additional electroreceptive pores that detect weak electrical signals from prey. Researchers have also studied the cephalofoil’s possible roles in maneuvering and pinning prey such as stingrays.

A common mix-up is calling the structure a “hammer” or “hammerhead,” which describes its appearance rather than its anatomical name. Cephalofoil is the precise term; it comes from Greek-derived roots referring to the head and leaf-like form.