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.

Chris Newbert / Scalloped Hammerhead Shark (Sphyrna lewini) school at 60 feet, Galapagos Islands, Ecuador

Norbert Wu / Scalloped Hammerhead Shark (Sphyrna lewini) schooling around a seamount, Cocos Island Costa Rica Pacific Ocean

Tui De Roy / Scalloped Hammerhead Shark (Sphyrna lewini) swimming along deep wall, Wenman Island, Galapagos Islands, Ecuador

Mark Jones / Scalloped Hammerhead Shark (Sphyrna lewini) schooling along deep wall, Wenman Island, Galapagos Islands, Ecuador

Fred Bavendam / Scalloped Hammerhead Shark (Sphyrna lewini) swimming among reef fish Galapagos Islands, Ecuador

Fred Bavendam / Scalloped Hammerhead Shark (Sphyrna lewini) close-up portrait Galapagos Islands, Ecuador, Ecuador

Fred Bavendam / Scalloped Hammerhead Shark (Sphyrna lewini) swimming among reef fish, Cocos Island, Costa Rica

Jeff Rotman / Scalloped hammerhead shark head portrait (Sphyrna lewini) Kanohe Bay, Hawaii.

Jeff Rotman / Hammerhead shark at night. (Sphyrnidae) Hawaii

Shane Gross / Great hammerhead shark (Sphyrna mokarran) swimming along coral reef wall. Exuma Cays Land and Sea Park, marine protected area, Bahamas.

Alex Mustard / Scalloped hammerhead shark (Sphyrna lewini) swims through a school of Pacific creolefish (Paranthias colonus). Wolf Island, Galapagos National Park, Galapagos Islands.. East Pacific Ocean.

Alex Mustard / Scalloped hammerhead shark (Sphyrna lewini) male in front of a school of Pacific creolefish (Paranthias colonus). Darwin Island, Galapagos National Park, Galapagos Islands. East Pacific Ocean.

Alex Mustard / Large school of Scalloped hammerhead sharks (Sphyrna lewini) in open water. Wolf Island, Galapagos National Park, Galapagos Islands. East Pacific Ocean.

Alex Mustard / Portrait of a large female scalloped hammerhead shark (Sphyrna lewini), with Pacific creolefish behind. Wolf Island, Galapagos National Park, Galapagos Islands. East Pacific Ocean.

Richard Robinson / Smooth hammerhead shark (Sphyrna zygaena) cruises on the surface at the edge of New Zealand's continental shelf.

Richard Robinson / Smooth hammerhead shark (Sphyrna zygaena) cruises on the surface at the edge of New Zealand's continental shelf.

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

Franco Banfi / Schooling Scalloped hammerhead sharks (Sphyrna lewini) Malpelo Island National Park, UNESCO World Heritage Site, Colombia, East Pacific Ocean. Endangered.

Franco Banfi / Schooling Scalloped hammerhead sharks (Sphyrna lewini) Malpelo Island National Park, UNESCO World Heritage Site, Colombia, East Pacific Ocean. Endangered.

Franco Banfi / Schooling Scalloped hammerhead sharks (Sphyrna lewini) Malpelo Island National Park, UNESCO World Heritage Site, Colombia, East Pacific Ocean. Endangered.

Franco Banfi / Schooling Scalloped hammerhead sharks (Sphyrna lewini) Malpelo Island National Park, UNESCO World Heritage Site, Colombia, East Pacific Ocean. Endangered

Franco Banfi / Schooling Scalloped hammerhead sharks (Sphyrna lewini) Malpelo Island National Park, UNESCO World Heritage Site, Colombia, East Pacific Ocean. Endangered

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

Alex Mustard / Diver photographing a female Great hammerhead shark (Sphyrna mokarran) in rough, turbid, shallow water. South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Stream, West Atlantic Ocean.

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

Alex Mustard / Great hammerhead sharks (Sphyrna mokarran) pair swimmingover seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Stream, West Atlantic Ocean.

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

Alex Mustard / A portrait of a female great hammerhead shark (Sphyrna mokarran) swimming over the seabed. South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Stream, West Atlantic Ocean. Hook in face...

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Front view of a Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Nurse shark (Ginglymostoma cirratum) resting on seabed with a Great hammerhead shark (Sphyrna mokarran) swimming nearby, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Oce...

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed with a Nurse shark (Ginglymostoma cirratum), Bar jacks (Caranx ruber) and Remora fish in the background, South Bimini, Bahamas. The...

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed being photographed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) being filmed by a scuba diver, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Close up of a Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) with tracking device and a diver in the background, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) being hand fed by a scuba diver, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Close up of Great hammerhead shark (Sphyrna mokarran) snout and mouth, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) being hand fed by a scuba diver, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed with resting Nurse sharks (Ginglymostoma cirratum), Bar jacks (Caranx ruber) and Remora fish, South Bimini, Bahamas. The Bahamas Na...

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed near resting Nurse sharks (Ginglymostoma cirratum), Bar jacks (Caranx ruber) and Remora fish, South Bimini, Bahamas. The Bahamas Na...

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) being hand-fed by a scuba diver on the seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Close up of a Great hammerhead shark (Sphyrna mokarran) being hand-fed by a scuba diver on the seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean. Model released.

Franco Banfi / Front view of a Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Close up of a Great hammerhead shark (Sphyrna mokarran) snout and mouth, being hand-fed by a scuba diver on the seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean...

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) being photographed by a scuba diver, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Close up if a Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) being hand-fed by a scuba diver on the seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean., South Bimini, Bahamas. The B...

Franco Banfi / Close up of a Great hammerhead shark (Sphyrna mokarran) snout and mouth, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Close up of a Great hammerhead shark (Sphyrna mokarran) snout and mouth,South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Franco Banfi / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, South Bimini, Bahamas. The Bahamas National Shark Sanctuary, West Atlantic Ocean.

Doug Perrine / Great hammerhead shark (Sphyrna mokarran) upper and lower teeth on display at Oceanographic Museum of Monaco, Principality of Monaco (digitally modified)

Franco Banfi / Scalloped hammerhead sharks (Sphyrna lewini) swimming shoal, Roca Partida close to San Benedicto island, Revillagigedo Archipelago Biosphere Reserve, Socorro Islands, Western Mexico

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

Alex Mustard / Great hammerhead shark (Sphyrna mokarran) female in shallow water. This individual has a rusted fishing hook through her hammer. South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Strea...

Alex Mustard / Bonnethead shark (Sphyrna tiburo) circling a pair of Foxface rabbitfish (Siganus vulpinus) which are protected by their venomous spines. Long Beach Aquarium, California, USA. North East Pacific Ocean....

Jordi Chias / Scalloped hammerhead (Sphyrna lewini) Roca Partida, Socorro Islands. Mexico, Pacific Ocean

Pete Oxford / MAR Alliance researchers with Great Hammerhead shark Sphyrna mokarran) captured for scientific research, Lighthouse Reef Atoll, Belize. May 2015.

Pete Oxford / Great Hammerhead shark (Sphryna mokarran) with fin mounted ARGOS satellite transponder by MAR Alliance, Lighthouse Reef Atoll, Belize. May 2015.

Norbert Wu / Great Hammerhead Shark (Sphyrna mokarran) and diver, Bimini, Bahamas, Caribbean

Norbert Wu / Great Hammerhead Shark (Sphyrna mokarran), Bimini, Bahamas, Caribbean

Norbert Wu / Great Hammerhead Shark (Sphyrna mokarran), Bimini, Bahamas, Caribbean

Pascal Kobeh / Scalloped hammerhead (Sphyrna lewini) in net. Malpelo Sanctuary, Colombia, Pacific Ocean.

Pascal Kobeh / Scalloped hammerhead (Sphyrna lewini) and a Silky shark (Carcharhinus falciformis) in a net. Malpelo Sanctuary, Colombia, Pacific Ocean.

Alex Mustard / Diver (Predrag Vuckovic) with large female Great hammerhead shark (Sphyrna mokarran) South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Stream, West Atlantic Ocean.

Franco Banfi / Painting of Hammerhead shark, Wafer Bay ranger station, Chatham Bay, Cocos Island National Park, Costa Rica, East Pacific Ocean. September 2012.

Pete Oxford / Great Hammerhead Shark (Sphyrna mokarran) dorsal fin with satellite transmitter, Lighthouse Reef, Belize

Juan Carlos Munoz / Great hammerhead (Sphyrna mokarran) swimming over people in underwater tunnel, Den Bla Planet aquarium, Copenhagen, Denmark, Europe, September 2014.

Pascal Kobeh / Silky shark (Carcharhinus falciformis) with a Scalloped hammerhead (Sphyrna lewini) in the background, Cocos island, Costa Rica. Pacific ocean.

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

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