What Divers Should Know About Scalloped Hammerhead

The Scalloped hammerhead (Sphyrna lewini) thrives in warm, temperate, and tropical coastal waters across the globe. This coastal pelagic species inhabits continental and insular shelves, extending into nearby deeper water down to 500 meters (1,600 ft). Most often, however, they are encountered above 25 meters (82 ft), frequently close to shore during daylight hours.

Recognizing this hammerhead is straightforward due to the distinct central indentation on its anterior head margin, flanked by two additional indentations, creating its characteristic 'scalloped' appearance. Their coloration typically ranges from uniform grey, grayish brown, bronze, or olive, with a lighter white underside for countershading. A large first dorsal fin, slightly hooked, also stands out. Mature males usually measure 1.5 to 1.8 meters (4.9-5.9 ft), while females are larger, reaching about 2.5 meters (8.2 ft) on average, with a maximum recorded length of 4.3 meters (14 ft).