John Cancalosi / Haloween / Red Land Crab (Gecarcinus quadratus). Costa Rican tropical rainforest.

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

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

Edwin Giesbers / Red / Halloween land crab (Gecarcinus quadratus), Costa Rica

Edwin Giesbers / Red / Halloween land crab (Gecarcinus Quadratus), Costa Rica

Jouan & Rius / Red / Halloween land crab (Gecarcinus quadratus) in mangrove, pacific coast, Costa Rica

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

Piotr Naskrecki / Black Land Crab (Gecarcinus ruricola) bright coloration combined with a pair of powerful claws make for a convincing threat display, Costa Rica

TJ Rich / Land crab (Gecarcinus lagostoma) Ascension Island

TJ Rich / Land crab (Gecarcinus lagostoma) dark coloration, Ascension Island

TJ Rich / Land crab (Gecarcinus lagostoma) in fissure in volcanic rock, Ascension Island