Juergen Freund / Mud crab (Scylla serrata) in shallow sandy water. Split level with island and thatched house on stilts. Moromahu Island, Wakatobi, South Sulawesi, Indonesia. Second Place in the Portfolio Award of the...

Juergen Freund / Horsehoe crab (Tachypleus gigas) swimming on its back with gills creating the propulsion, Palawan, Philippines. Did you know? Horseshoe crabs are more closely related to spiders than crabs.

Lynn M. Stone / White ibis (Eudocimus albus) in winter plumage, eating Atlantic blue crab (Callinectes sapidus), at edge of saltwater lagoon. St. Petersburg, Florida, USA (non-ex)

Lynn M. Stone / White ibis (Eudocimus albus) in winter plumage, eating Atlantic blue crab (Callinectes sapidus), at edge of saltwater lagoon. St. Petersburg, Florida, USA

SCOTLAND: The Big Picture / Harbour crab (Liocarcinus depurator) in maerl bed, South Arran Marine Protected Area, Isle of Arran, Scotland, UK, August.

SCOTLAND: The Big Picture / Harbour crab (Liocarcinus depurator) in maerl bed within no take zone, South Arran Marine Protected Area, Isle of Arran, Scotland, UK, August.

SCOTLAND: The Big Picture / Harbour crab (Liocarcinus depurator) in maerl bed, South Arran Marine Protected Area, Isle of Arran, Scotland, UK, August.

Pascal Kobeh / Flower / Blue swimmer / Sand crab (Portunus pelagicus) on sea floor, Sulu Sea, Philippines

Pascal Kobeh / Flower / Blue / Blue swimmer / Sand crab (Portunus pelagicus) Sulu Sea, Philippines

Aflo / Blue crab (Portunus trituberculatus) Oyano, Kumamoto Prefecture, Japan. October.

Sue Daly / Female Harbour Crab with eggs (Liocarcinus depurator) Bouley Bay, Jersey, British Channel Islands.

Staffan Widstrand / Crab (Portunus sanguinolentus) Pulicat Lake, Tamil Nadu, India, February 2013.

Norbert Wu / Blue Swimming Crab (Portunus pelagicus) pair mating, South Australia, Australia

Juergen Freund / A factory of women taking the meat out of cooked Blue swimmer crabs (Portunus pelagicus) to pack for export to America. Northern Palawan, Phillipines, May 2009

Juergen Freund / Blue swimmer crab (Portunus pelagicus) on the sea bed. Lembeh Strait, North Sulawesi, Indonesia

Fred Bavendam / Southern Keeled Octopus (Octopus berrima) with a Sand Crab (Ovalipes sp) it has captured to eat, Edithburgh, South Australia

Fred Bavendam / Blue Swimming Crab (Portunus pelagicus) with its claws spread wide in a defensive posture, Edithburgh, South Australia, Australia

Gary Bell/ Oceanwide / Blue Swimming Crab (Portunus pelagicus) pair mating, Edithburgh, Yorke Peninsula, South Australia, Australia

Gary Bell/ Oceanwide / Blue Swimming Crab (Portunus pelagicus) in defensive posture, Yorke Peninsula, South Australia, Australia

Donald M. Jones / Blue Grouse (Dendragapus obscurus) male calling, western Montana

Carine Schrurs / Blue swimming crab pair mating {Portunus pelegicus} male underneath Batangas Philippines

Joel Sartore / Photo Ark / Turtle barnacle (Chelonibia testudinaria) on the shell of a Common blue crab (Callinectes sapidus) portrait, Gulf Specimen Marine Lab, Florida. Captive.

Joel Sartore / Photo Ark / Lesser blue crab (Callinectes similis) portrait, Gulf Specimen Marine Lab, Florida, USA. Captive.

Joel Sartore / Photo Ark / Lesser blue crab (Callinectes similis) portrait, Gulf Specimen Marine Lab, Florida, USA. Captive.

Joel Sartore / Photo Ark / Lesser blue crab (Callinectes similis) portrait, Gulf Specimen Marine Lab, Florida, USA. Captive.

Joel Sartore / Photo Ark / Lesser blue crab (Callinectes similis) close up, moving antennae and mandibles, Gulf Specimen Marine Lab. Captive.

Franco Banfi / Portunid crab (Liocarcinus depurator), mating pair, Vevang, Norway, Atlantic Ocean.

Franco Banfi / Portunid crab (Liocarcinus depurator) scuttling across the seabed, Trondheimfjord, Norway, North Atlantic Ocean.

Shane Gross / Atlantic blue crab (Callinectes sapidus) hunting in Turtlegrass (Thalassia testudinum) seagrass bed, view towards sky. Florida Keys, Florida, USA.

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

Claudio Contreras / Crab fisherman Celestun with Blue Crab (Callinectes sp.) catch, Ria Celestun Biosphere Reserve, Yucatan Peninsula, Mexico, February