Gary Bell/ Oceanwide / Grey Nurse Shark (Carcharias taurus), Solitary Islands Marine Park, New South Wales, Australia

Chris & Monique Fallows / Blue Shark (Prionace glauca) tail, Cape Point, South Africa.

Cheryl-Samantha Owen / Blacktip reef shark (Carcharhinus melanopterus) approaching Grey heron (Ardea cinerea) in shallow water, Aldabra Atoll, Seychelles, Indian Ocean

Ian Coleman / Illustration of Grey reef shark (Carcharhinus amblyrhynchos), Carcharhinidae. Endangered / threatened species.

Ian Coleman / Illustration of Great white shark (Carcharodon carcharias), Lamnidae. Endangered / threatened species.

Alex Mustard / View of gills and gill rakers of a Basking shark (Ceterhinus maximus) as it feeds in Cornwall, England. UK, East Atlantic Ocean. June

Alex Mustard / Tiger shark (Galeocerdo cuvier) portrait over white sand. Little Bahama Bank, Bahamas.

Alex Mustard / Oceanic whitetip shark (Carcharhinus longimanus) with Pilot fish (Naucrates ductor). Tropical West Atlantic Ocean, off Cat Island, Bahamas.

Juergen Freund / Richard Fitzpatrick releases Grey reef shark {Carcharhinus amblyrhynchos} after inserting transmitter into its belly, as part of the Coral Reef census, Lizard Island, Queensland, Australia, April 2008

Juergen Freund / Whitetip reef shark (Triaenodon obesus) and Grey reef sharks (Carcharhinus amblyrhynchos) at North Horn, Queensland, Australia

Juergen Freund / Grey reef sharks (Carcharhinus amblyrhynchos) at North Horn, Queensland, Australia

Juergen Freund / Grey Reef sharks (Carcharhinus amblyrhynchos) at North Horn teeming at water surface

Doug Perrine / School of Grey reef sharks {Carcharhinus amblyrhynchos}, Micronesia.

Doug Perrine / School of Grey reef sharks {Carcharhinus amblyrhynchos} on coral reef Micronesia.

Doug Perrine / School of Grey reef sharks {Carcharhinus amblyrhynchos} Micronesia.

Doug Perrine / School of Grey reef sharks {Carcharhinus amblyrhynchos} near surface Micronesia.

Fred Bavendam / Grey Reef Shark (Carcharhinus amblyrhynchos) feeding on a large baitfish ball, Solomon Islands, South Pacific

Fred Bavendam / Grey Reef Shark (Carcharhinus amblyrhynchos) feeding on a large baitfish ball, Solomon Islands

Doug Perrine / Grey reef shark group {Carcharhinus amblyrhynchos} Bikini Atoll, Micronesia, Pacific Ocean (Non-ex).

Juergen Freund / Grey reef shark dead on seabed after removal of fins {Carcharhinus amblyrhynchos} Philippines

Juergen Freund / Grey reef shark {Carcharhinus amblyrhynchos} with Remora fish, Great Barrier reef, Queensland, Australia

Michael Pitts / Grey reef shark {Carcharhinus amblyrhynchos} Nassau, Bahamas, Caribbean

Michael Pitts / Grey reef shark close up {Carcharhinus amblyrhynchos} Grand Bahamas, Caribbean

Gary Bell/ Oceanwide / Grey Nurse Shark (Carcharias taurus) and diver, Solitary Islands Marine Park, New South Wales, Australia

Gary Bell/ Oceanwide / Grey Nurse Shark (Carcharias taurus), Fish Rock, New South Wales, Australia

Gary Bell/ Oceanwide / Grey Nurse Shark (Carcharias taurus), Fish Rock, New South Wales, Australia

Gary Bell/ Oceanwide / Grey Nurse Shark (Carcharias taurus) scraping parasites off in sand, Solitary Islands Marine Park, New South Wales, Australia

Gary Bell/ Oceanwide / Grey Nurse Shark (Carcharias taurus), Solitary Islands Marine Park, New South Wales, Australia

Gary Bell/ Oceanwide / Grey Nurse Shark (Carcharias taurus), Solitary Islands Marine Park, New South Wales, Australia

Gary Bell/ Oceanwide / Grey Nurse Shark (Carcharias taurus), Solitary Islands Marine Park, New South Wales, Australia

Richard Robinson / Thicklipped jack (Pseudocaranx dentex ) swimming in front of nose of Grey Reef Shark (Carcharhinus amblyrhynchos) at North Minerva Reef / Teleki Tokelau a disputed territory in the South Pacific bet...

David Fleetham / Grey reef shark (Carcharhinus amblyrhynchos), opens it's mouth during a shark feed off the island of Yap, Micronesia.

David Fleetham / Fijian dive guide feeding Grey reef shark (Carcharhinus amblyrhynchos) off Mana Island, Fiji.

David Fleetham / Grey reef shark (Carcharhinus amblyrhynchos) and Whitetip reef shark (Triaenodon obesus) off Mana Island, Fiji.

David Fleetham / Grey reef sharks (Carcharhinus amblyrhynchos) Yap, Micronesia.

David Fleetham / Grey reef shark (Carcharhinus amblyrhynchos) by bait box during organized feeding in Yap, Micronesia.

David Fleetham / Grey reef shark (Carcharhinus amblyrhynchos) hooked with fishing line, Hawaii.

David Fleetham / Black tip reef shark (Carcharhinus melanopterus) and grey reef sharks (Carcharhinus amblyrhynchos), Yap, Micronesia.

David Fleetham / Grey reef sharks (Carcharhinus amblyrhynchos) on reef, Yap, Micronesia.

David Fleetham / Grey reef shark (Carcharhinus amblyrhynchos) swimming with yellow juvenile jacks off the island of Yap, Micronesia.

David Fleetham / Group of grey reef sharks (Carcharhinus amblyrhynchos) feeding on bait off Yap, Micronesia.

David Fleetham / Grey reef sharks (Carcharhinus amblyrhynchos) pair on reef. Yap, Micronesia.

Franco Banfi / Grey reef shark (Carcharhinus amblyrhynchos) North Point dive site, Sanganeb reef, Sudan, Red Sea

Franco Banfi / Greenland shark (Somniosus microcephalus) under ice, Lancaster Sound, Nunavut, northern Baffin Island, Canada, Arctic.

Franco Banfi / Greenland shark (Somniosus microcephalus) with parasitic copepod (Ommatokoita elongata), under ice, Lancaster Sound, Nunavut, northern Baffin Island, Canada, Arctic.

Franco Banfi / Greenland shark (Somniosus microcephalus) with parasitic copepod (Ommatokoita elongata), under ice, Lancaster Sound, Nunavut, northern Baffin Island, Canada, Arctic.

Franco Banfi / Greenland shark (Somniosus microcephalus) under ice, Lancaster Sound, Nunavut, northern Baffin Island, Canada, Arctic.

Franco Banfi / Greenland shark (Somniosus microcephalus) with parasitic copepod (Ommatokoita elongata), under ice, Lancaster Sound, Nunavut, northern Baffin Island, Canada, Arctic.

Doug Perrine / Grey reef shark (Carcharhinus amblyrhynchos) upper and lower teeth, on display at Oceanographic Museum of Monaco, Principality of Monaco (digitally modified)

Jordi Chias / Grey reef sharks (Carcharhinus amblyrhynchos) in the south pass of Fakarava Tuamotus, French Polynesia, South Pacific

Melvin Grey / Green-backed heron (Butorides striatus virescens) adult male, Shark Valley, Florida, USA, February.

Juergen Freund / Grey reef sharks (Carcharhinus amblyrhynchos) group, one with Remora (Remora) Coral Sea, Great Barrier Reef, Queensland, Australia.

Pascal Kobeh / Grey reef shark (Carcharhinus amblyrhinchos) heads in lagoon of fishermen island, Maldives, Indian Ocean, Baa Atoll. 1998

Franco Banfi / Greenland shark (Somniosus microcephalus) with parasitic copepod (Ommatokoita elongata), under ice, Lancaster Sound, Nunavut, northern Baffin Island, Canada, Arctic.

Pascal Kobeh / Two Grey reef sharks (Carcharhinus amblyrhynchos) in a school of Bonitos / Amberjacks (Sarda ou Seriola ) Palau. Philippine Sea.

Pascal Kobeh / Grey reef shark (Carcharhinus amblyrhinchos) surrounded by Bigeye trevally / jacks (Caranx sexfasciatus) Palau. Philippine Sea.

Pascal Kobeh / Grey reef shark (Carcharhinus amblyrhinchos) in open water with a Striped remora (Echeneis naucrates) under its head, Palau. Philippine Sea.

Pascal Kobeh / Grey reef sharks (Carcharhinus amblyrhinchos) in open water. The shark on foreground has a Striped remora (Echeneis naucrates) under its head, Palau. Philippine Sea.

Pascal Kobeh / Grey reef sharks (Carcharhinus amblyrhinchos) in open water with a Striped remora (Echeneis naucrates) under its head, Palau. Philippine Sea.

Pascal Kobeh / Grey reef sharks (Carcharhinus amblyrhinchos) in open water. The shark on foreground has a Striped remora (Echeneis naucrates) under its head, Palau. Philippine Sea.

Pete Oxford / Grey Reef Shark (Carcharhinus amblyrhynchos), Beqa Lagoon, Viti Levu, Fiji

Chris & Monique Fallows / Great white shark (Carchardon carcharias) with Pilot fish (Naucrates ductor) Isla Guadalupe, Mexico

Chris & Monique Fallows / Blue shark (Prionace glauca), rear view with Pilot fish (Naucrates ductor) Cape Point, South Africa

Pete Oxford / Grey Nurse Shark (Carcharias taurus), Umkomaas, Kwazulu Natal, South Africa

Juergen Freund / Grey reef sharks (Carcharhinus amblyrhynchos) in Great Barrier Reef, Coral Sea, Queensland, Australia

Juergen Freund / Grey reef sharks (Carcharhinus amblyrhynchos) in Great Barrier Reef, Coral Sea, Queensland, Australia

Juergen Freund / Grey reef sharks (Carcharhinus amblyrhynchos) in Great Barrier Reef, Coral Sea, Queensland, Australia

Juergen Freund / Whale shark (Rhincodon typus) feeding on fish near a fishing device called ?Bagan?, a stationary outrigger boat, with a net between outriggers and strong light at night to attract anchovies and scad....

Juergen Freund / Whitetip reef shark (Triaenodon obesus) and Grey reef sharks (Carcharhinus amblyrhynchos) Great Barrier Reef, Coral Sea, Queensland, Australia

Juergen Freund / Grey reef sharks (Carcharhinus amblyrhynchos) in Great Barrier Reef, Coral Sea, Queensland, Australia

Juergen Freund / Whitetip reef shark (Triaenodon obesus) and Grey reef sharks (Carcharhinus amblyrhynchos) Great Barrier Reef, Queensland, Australia

Juergen Freund / Grey reef sharks (Carcharhinus amblyrhynchos) in Great Barrier Reef, Coral Sea, Queensland, Australia

Juergen Freund / Grey reef sharks (Carcharhinus amblyrhynchos) in Great Barrier Reef, Coral Sea, Queensland, Australia

Juergen Freund / Sharks, mainly grey reef sharks (Carcharinus amblyrhynchos) feed at bait, North Horn, Osprey Reef, Coral Sea, January

Franco Banfi / Grey reef shark (Carcharhinus amblyrhynchos) patrolling reef, Maldives, Indian Ocean

Franco Banfi / Grey reef shark (Carcharhinus amblyrhynchos) Maldives, Indian Ocean

Franco Banfi / Shooling Grey reef sharks (Carcharhinus amblyrhynchos) Maldives, Indian Ocean

Franco Banfi / Grey reef shark (Carcharhinus amblyrhynchos) Maldives, Indian Ocean

Franco Banfi / Grey reef sharks (Carcharhinus amblyrhynchos) swimming though shoal of fish, Maldives, Indian Ocean

Franco Banfi / Grey reef shark (Carcharhinus amblyrhynchos) swimming through shoal of fish, Maldives, Indian Ocean

Alex Mustard / Whale shark (Rhincodon typus) mouth open filter feeding at the surface, Quintana Roo, Yucatan Peninsular, Mexico, Caribbean Sea.

Cheryl-Samantha Owen / Grey reef shark (Carcharhinus amblyrhynchos), Aldabra Atoll, Seychelles, Indian Ocean

Cheryl-Samantha Owen / Blacktip reef shark (Carcharhinus melanopterus) approaching Grey heron (Ardea cinerea) in shallow water, Aldabra Atoll, Seychelles, Indian Ocean

Cheryl-Samantha Owen / Blacktip reef sharks (Carcharhinus melanopterus) approaching Grey heron (Ardea cinerea) in shallow water, Aldabra Atoll, Seychelles, Indian Ocean

Alex Mustard / A large female Grey nurse /Sand Tiger / Ragged-tooth Shark (Carcharias taurus) Fish Rock, Southwest Rock, New South Wales, Australia. Pacific Ocean. In the final stages of pregancy, female gray nurse...

Alex Mustard / Grey nurse /Sand Tiger / Ragged-tooth Shark (Carcharias taurus) Fish Rock, Southwest Rock, New South Wales, Australia. Pacific Ocean. November

Alex Mustard / Grey nurse /Sand Tiger / Ragged-tooth Shark (Carcharias taurus) close up, Fish Rock, Southwest Rock, New South Wales, Australia. Pacific Ocean. November

Alex Mustard / Grey nurse /Sand Tiger / Ragged-tooth Shark (Carcharias taurus) Fish Rock, Southwest Rock, New South Wales, Australia. Pacific Ocean. November

Juergen Freund / Richard Fitzpatrick inserting radio transmitter into skin of Grey reef shark {Carcharhinus amblyrhynchos} part of the Coral Reef census, Lizard Island, Queensland, Australia, April 2008

Juergen Freund / Richard Fitzpatrick inserting depth and time recording device to base of dorsal fin of Grey reef shark {Carcharhinus amblyrhynchos} part of the Coral Reef census, Lizard Island, Queensland, Australia,...

Juergen Freund / Richard Fitzpatrick inserting radio transmitter into skin of Grey reef shark {Carcharhinus amblyrhynchos} part of the Coral Reef census, Lizard Island, Queensland, Australia, April 2008

Juergen Freund / Richard Fitzpatrick sewing up a Grey reef shark {Carcharhinus amblyrhynchos} after inserting transmitter into its belly, as part of the Coral Reef census, Lizard Island, Queensland, Australia, April 2...

Juergen Freund / Richard Fitzpatrick sewing up a Grey reef shark {Carcharhinus amblyrhynchos} after inserting transmitter into its belly, as part of the Coral Reef census, Lizard Island, Queensland, Australia, April 2...

Fred Bavendam / Grey Nurse Shark (Carcharias taurus) underwater portrait, New South Wales, Australia

Fred Bavendam / Grey Nurse Shark (Carcharias taurus) swimming over reef, New South Wales, Australia