The
coconut crab (Birgus latro) is a species of terrestrial hermit crabs that's known for the
largest land-living arthropod in the world, weighing up to 4.1 kg (9.0 lb). It is found on islands across the Indian Ocean and parts of the Pacific Ocean, mirroring the distribution of the coconut palm. Like other hermit crabs, juvenile coconut crabs use empty gastropod shells for protection, but the adults develop a tough exoskeleton on their abdomen and stop carrying a shell.
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. They have also developed an acute sense of smell, which has evolved convergently with ...