To about 18.5 ft (5.6 m).
- Head nearly straight and hammer-shaped, marked by prominent indentation at midline
- First dorsal fin tall and strongly curved
- Color dark olive green to brownish-gray above, shading to white below
- No interdorsal ridge
Massachusetts to Brazil, including Gulf of Mexico and Caribbean Sea. Common off Carolinas in summer. Rare north of North Carolina.
Coastal and offshore; near surface to >250 ft (76 m).
Bonnethead has shovel-shaped head; growns to about 5 ft (1.5 m). Smooth Hammerhead and Scalloped Hammerhead have swept-back "hammers," smaller first dorsal fins, pelvic fins with straight rear margins. Smooth Hammerhead lacks central indentation in "hammer."
Text descriptions taken from:
Guide to Sharks, Tunas, & Billfishes
of the U.S. Atlantic and Gulf of Mexico