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

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.

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

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

MYN / Paul Marcellini / Sargassum crab (Portunus sayi) Biscayne National Park, Florida, USA, April. meetyourneighbours.net project

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

Martha Holmes / Swimming crab in defensive position {Portunus sebae} Grenadines, Caribbean

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

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 / Iridescent swimming crab (Portunus gibbesii) dorsal view, Gulf Specimen Marine Lab and Aquarium. Captive.

David Fleetham / Ocellate swimming crab (Portunus sebae) on sandy sea floor, photographed off Singer Island, Atlantic Ocean, Florida, USA.

Francisco Marquez / Swimming crab (Portunus) on white background, Islas Marias Archipelago, Marias Biosphere Reserve, Mexico.

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.

Shane Gross / Sargassum swimming crab (Portunus sayi) taking shelter in a plastic bag. Contoy Island, Mexico.

Shane Gross / Sargassum swimming crab (Portunus sayi) at night in the Sargasso Sea, Atlantic Ocean, International Waters.