malformalady:

The coconut crab(Birgus latro), is a species of terrestrial hermit crab, also known as the robber crab or palm thief. It is the largest land-living arthropod in the world, with a weight of up to 4.1 kg (9.0 lb).  It is found on islands across the Indian Ocean and parts of the Pacific Ocean. Coconut crabs have evolved organs known as “branchiostegal lungs”, which are used instead of the vestigial gills for breathing. They cannot swim, and will drown if immersed in water for long. Adult coconut crabs feed on fruits, nuts, seeds, and the pith of fallen trees, but will eat carrion and other organic matter opportunistically. The species is popularly associated with the coconut, and has been widely reported to climb trees to pick coconuts, which it then opens to eat the flesh.