Scalloped hammerheads can form seasonal aggregations or live solitary. Both migrating and stationary populations are known. Average size between 8 and 10 ft, maximum total length about 14 ft. Gestation period lasts between 9 and 10 months. Males reach sexual maturity at about 4.5 to 5 ft.
Body is compressed-cylindrical and moderately stout.
First and second dorsal fin are equal sized with a broad base. Origin of first dorsal fin well behind the free rear ends of the pectoral fins. Origin of second dorsal fin slightly ahead of anal fin's origin. Anal fin is approximately the same size as the two dorsal fins. Upper caudal pit is present.