David Perpinan / Black land crab (Gecarcinus ruricola) at night in San Andres island, Colombia.

David Perpinan / Black land crab (Gecarcinus ruricola) at night, San Andres island, Caribbean Colombia.

Jane Burton / Common land crab {Gecarcinus ruricola} on leaves. Barbados, West Indies.

Kevin Schafer / Purple Land Crab (Gecarcinus ruricola) juvenile, Zapata Peninsula, Cuba

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

Kevin Schafer / Purple Land Crab (Gecarcinus ruricola) in intertidal zone, Zapata Peninsula, Cuba

Kevin Schafer / Purple Land Crab (Gecarcinus ruricola), Zapata Peninsula, Cuba