Red Rock Crab

The crab Grapsus grapsus, known variously as "Red Rock Crab", is one of the most common crabs along the western coast of South America. It can also be seen along the entire Pacific coast of Central America and Mexico, and nearby islands.

The Red Rock Crab is a typically-shaped crab, with five pairs of legs, the front two bearing small, blocky, symmetrical chelae. The other legs are broad and flat, with only the tips touching the substrate. The crab's round, flat carapace is just over 8 cm in length. Young Red Rock Crabs are black or dark brown in color and camouflage well on the black lava coasts of volcanic islands. Adults are quite variable in color. Some are muted brownish-red, some mottled or spotted brown, pink, or yellow. The ones seen on photographs of tropical island fauna are often bright orange or red with stripes or spots dorsally, blue and green ventrally, and sporting red claws and pink or blue eyes.

This crab lives amongst the rocks at the often turbulent, windy shore, just above the limit of the seaspray. It feeds on algae primarily. It is a quick-moving and agile crab.

Source: en.wikipedia.org/wiki/Grapsus_grapsus - 20.05.2010