Ingo Arndt / Blue Crab (Discoplax hirtipes) in defensive posture, Christmas Island, Indian Ocean, Territory of Australia

Stephen Belcher / Christmas Island Red Crab (Gecarcoidea natalis) and Blue Crab (Discoplax hirtipes) carcasses, death caused by Yellow Crazy Ants (Anoplolepis gracilipes), Christmas Island National Park, Christmas Isla...

Stephen Belcher / Christmas Island Red Crab (Gecarcoidea natalis) and Blue Crab (Discoplax hirtipes) carcasses, death caused by Yellow Crazy Ants (Anoplolepis gracilipes), Christmas Island National Park, Christmas Isla...

Juergen Freund / Thousands of newly hatched baby Land crabs emerging from the sea where they lived as planktonic larvae and are now ready to go back to the forest for their adult lives. Bird's Head Peninsula, West Pap...

Pete Oxford / Blackback Land Crab (Gecarcinus lateralis) in defensive posture, Zapata Swamp National Park, Cuba

Edwin Giesbers / Land crab (Gecarcinidae) on moss in tropical forest, Sarawak Borneo, Malaysia,

Alex Hyde / Forest Crab on plant leaf at night in rainforest, Masoala Peninsula National Park, north east Madagascar.

Konrad Wothe / Halloween Crab (Gecarcinus quadratus) in defensive posture on beach, Manuel Antonio National Park, Costa Rica

Tim Laman / Unidentified land crab from Panay Island Northwest mountains, Philippines. May

Albert Lleal / Blue Land Crab (Cardisoma guanhumi) in defensive posture, Juventud Island, Cuba

Luciano Candisani / Yellow and Purple Land Crab (Gecarcinus lagostoma) in defensive position, Rocas Atoll, Brazil

Luciano Candisani / Yellow and Purple Land Crab (Gecarcinus lagostoma) walking on the beach at night, Rocas Atoll, Brazil