Jeff Rotman / Head and gills of juvenile Scalloped hammerhead shark (Sphyrna Lewini), Kane'ohe Bay, Hawaii, Pacific Ocean.

Doug Perrine / Female scalloped hammerhead shark, Sphyrna lewini, off Keauhou, South Kona, Big Island, Hawaii, USA ( Central Pacific Ocean )

Doug Perrine / Female scalloped hammerhead shark, (Sphyrna lewini) off Keauhou, South Kona, Big Island, Hawaii, Central Pacific Ocean

Alex Mustard / Great hammerhead shark (Sphyrna mokarran) female at night with Bar jacks (Caranx ruber), South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Stream, West Atlantic Ocean.

Alex Mustard / Great hammerhead shark (Sphyrna mokarran) male in shallow water. South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Stream, West Atlantic Ocean.

Alex Mustard / Great hammerhead shark (Sphyrna mokarran) swimming over a sandy seabed, accompanied by Rainbow runners (Elagatis bipinnulata) South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Stream,...

Alex Mustard / Diver (Predrag Vuckovic) is dwarfed by Great hammerhead shark (Sphyrna mokarran). This species can reach over 6m in length. South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Stream, We...

Franco Banfi / Schooling Scalloped hammerhead sharks (Sphyrna lewini) Cocos Island National Park, Costa Rica.

Richard Herrmann / Smooth Hammerhead Shark (Sphyrna zygaena), Nine Mile Bank, San Diego, California

Pascal Kobeh / Scalloped hammerhead (Sphyrna lewini), Cocos Island , Costa Rica. Pacific Ocean.

Michele Westmorland / Large school of scalloped hammerhead sharks (Sphyrna lewini). Galapagos Islands.

Alex Mustard / A large Great hammerhead shark (Sphyrna mokarran), about 4m in length, cruises overhead. Bahamas, Tropical West Atlantic Ocean.