Hammerhead sharks are the most distinguishable sharks in the sea, but there are slight nuances that separate common species. If you are on a dive and get a close look — or if you snap a few photos — keep an eye on these features.

Head shape

Of course, all hammerhead sharks can be identified by heads that expand laterally, making the shape of a hammer. But the great hammerhead — Sphyrna mokarran — is set apart from the scalloped and smooth hammerheads by its straight frontal head. The great hammerhead, which also has a notch in the center of its head, makes more of a T shape with its head, while the scalloped and smooth hammerheads are more rounded, almost resembling a shovel.

Notch

The scalloped hammerhead — Sphyrna lewini — has a much more pronounced notch, or scallop, at the midpoint of its head, which is also more curved. The smooth hammerhead — Sphyrna zygaena — has a slightly curved head, but can be easily identified by its lack of a notch or scallop at the midpoint of its head. One could even call it smooth.

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