Doug Perrine / Schooling female Scalloped hammerhead shark (Sphyrna lewini), Big Island, Hawaii, Pacific Ocean.

Andy Murch / Smooth hammerhead shark (Sphyrna zygaena). Cabo San Lucas, Baja California Sur, Mexico.

Andy Murch / Scoophead shark (Sphyrna media), released specimen. Isla Chepillo, Rio Bayano, Panama.

Andy Murch / Red stingray (Hemitrygon akajei) with Banded houndshark (Triakis scyllium) group and smaller fish in background. Chiba Prefecture, Honshu, Japan. September.

Andy Murch / Lemon shark (Negaprion brevirostris) surfacing with open mouth. Tiger Beach, Little Bahama Bank, Bahamas.

Andy Murch / Great hammerhead shark (Sphyrna mokarran) mouth wide open, feeding in shallow water, surrounded by fish. South Bimini Island, Bahamas.

Andy Murch / Bronze whaler shark (Carcharhinus brachyurus) group feeding alongside Cape gannet (Morus capensis) during sardine run. Wild Coast, Eastern Cape, South Africa. June.

Andy Murch / Banded houndshark (Triakis scyllium) group above sea floor. Chiba Prefecture, Honshu, Japan. October.

Shane Gross / Lemon shark juvenile (Negaprion brevirostris) swimming in mangrove habitat near blue crab (Callinectes sapidus), a prey species for the shark. Eleuthera, Bahamas.

Shane Gross / Lemon shark juvenile (Negaprion brevirostris) trying to feed on the leaves of a red mangrove (Rhizophora mangle). As pups, the sharks have to learn to hunt for themselves and sometimes make mistakes....

Sirachai Arunrugstichai / Requiem sharks (Carcharhinidae), including Tiger sharks (Galeocerdo cuvier) and Spottail sharks (Carcharhinus sorrah) caught in the Andaman Sea by longline fishing. Laid in buckets, waiting to be tran...

Brandon Cole / Grey reef sharks (Carcharhinus amblyrhynchos), schooling, French Polynesia, Pacific Ocean.

Brandon Cole / Crescent-tail bigeyes (Priacanthus hamrur), and Grey reef sharks (Carcharhinus amblyrhynchos). French Polynesia, Pacific Ocean.

Brandon Cole / Oceanic whitetip shark (Carcharhinus longimanus), view from above as it swims away. Egypt, Red Sea.

Brandon Cole / Oceanic whitetip shark (Carcharhinus longimanus) and Pilotfish (Naucrates ductor) swimming under a stormy surface. Egypt, Red Sea.

Brandon Cole / Silky shark (Carcharhinus falciformis), feeding on small fish, juvenile Bigeye jacks (Caranx sexfasciatus) in baitball. Baja, Mexico, Pacific Ocean.

Claudio Contreras / Silky Shark (Carcharhinus falciformis) with hook, Jardines de la Reina / Gardens of the Queen National Park, Caribbean Sea, Ciego de Avila, Cuba.

Claudio Contreras / Black grouper (Mycteroperca bonaci), and Caribbean Reef Shark (Carcharhinus perezi), Jardines de la Reina / Gardens of the Queen National Park, Caribbean Sea, Ciego de Avila, Cuba.

Claudio Contreras / Black grouper (Mycteroperca bonaci), and Caribbean Reef Shark (Carcharhinus perezi), Jardines de la Reina / Gardens of the Queen National Park, Caribbean Sea, Ciego de Avila, Cuba.

Claudio Contreras / Caribbean Reef Shark (Carcharhinus perezi) group of three, Jardines de la Reina / Gardens of the Queen National Park, Caribbean Sea, Ciego de Avila, Cuba.

Alex Mustard / A shiver of Caribbean reef sharks (Carcharhinus perezi) swim over a coral reef with Common sea fans (Gorgonia ventalina) and sea plumes (Pseudopterogorgia sp). Jardines de la Reina, Gardens of the Que...

Alex Mustard / A vibrant Caribbean coral reef with two Reef sharks (Carcharhinus perezi) and Common sea fans (Gorgonia ventalina) and sea plumes (Pseudopterogorgia sp). Jardines de la Reina, Gardens of the Queen Nat...

Shane Gross / A Great hammerhead shark (Sphyrna mokarran) swimming towards the camera, Bimini, Bahamas.

Shane Gross / Great hammerhead shark (Sphyrna mokarran) swimming over sandy seabed, Bimini, Bahamas.

Shane Gross / A Giant clam (Tridacna gigas) surrounded by Lettuce coral (Turbinaria reniformis), Kosrae, Micronesia.

Franco Banfi / Blue shark (Prionace glauca) and Pilot fish (Naucrates ductor), Pico Island, Azores, Portugal, Atlantic Ocean

Franco Banfi / Blue shark (Prionace glauca) with fishing hook caught in mouth and Pilot fish (Naucrates ductor), Pico Island, Azores, Portugal, Atlantic Ocean

Shane Gross / Two Caribbean reef shark (Carcharhinus perezi) one with a fishing hook and line and one with a broken jaw from catch and release shark fishing. The Bahamas.

Shane Gross / Face portrait of a Great hammerhead shark (Sphyrna mokarran) off Bimini, Bahamas.

Shane Gross / Great hammerhead shark (Sphyrna mokarran) swimming over a sandy seabed, Bimini, Bahamas

Alex Mustard / Oceanic whitetip shark (Carcharhinus longimanus) is framed by the surface. Elphinstone reef, Marsa Alam, Egypt. Red Sea.

Alex Mustard / Oceanic whitetip shark (Carcharhinus longimanus) swimming close to surface. Brothers Islands, Egypt.

Alex Mustard / Blacktip reef shark (Carcharhinus melanopterus) swims through schools of fish. Misool, Raja Ampat, West Papua, Indonesia. Ceram Sea. Tropical West Pacific Ocean.

Nick Hawkins / Blue shark (Prionace glauca) with a pair of pilot fish (Naucrates ductor) off Halifax, Nova Scotia, Canada. July.

Nick Hawkins / Blue shark (Prionace glauca) off Halifax, Nova Scotia, Canada. July.

Nick Hawkins / Overhead view of a blue shark (Prionace glauca) off Halifax, Nova Scotia, Canada. July.

Shane Gross / Caribbean reef shark (Carcharhinus perezi) patrolling coral reef with Schoolmaster snapper (Lutjanus apodus) and other fish. Caribbean Sea off Gardens of the Queen National Park, Cuba.

Shane Gross / Silky shark (Carcharhinus falciformis), three in Caribbean Sea off Gardens of the Queen National Park, Cuba.

Shane Gross / Caribbean reef shark (Carcharhinus perezi), two from below, one close up. Caribbean Sea off Gardens of the Queen National Park, Cuba.

Tony Wu / Blacktip reef shark (Carcharhinus melanopterus) beaching itself to catch sardines. Tonga South Pacific.

Pascal Kobeh / Blue shark (Prionace glauca) Azores, Atlantic Ocean.

Shane Gross / Lemon shark pup (Negaprion brevirostris) in mangrove forest which acts as a nursery for juveniles of this species. Eleuthera, Bahamas.

Shane Gross / Lemon shark pup (Negaprion brevirostris) in mangrove forest which acts as a nursery for juveniles of this species. Eleuthera, Bahamas.

Shane Gross / Lemon shark pup (Negaprion brevirostris) in mangrove forest which acts as a nursery for juveniles of this species. Eleuthera, Bahamas.

Shane Gross / Lemon shark pup (Negaprion brevirostris) in mangrove forest which acts as a nursery for juveniles of this species. Eleuthera, Bahamas.

Nick Hawkins / Silky shark (Carcharhinus falciformis). Cocos Island National Park, Costa Rica.

David Fleetham / Blacktip reef shark (Carcharhinus melanopterus) swimming just below surface at sunset, split level view. Off the island of Yap, Micronesia.

David Fleetham / Whitetip reef shark (Triaenodon obesus) resting on sea floor. Kauai, Hawaii.