Red Rock Crab (Grapsus grapsus)

Red Rock Crab (Grapsus grapsus (Linnaeus, 1758))

Scientific name: Grapsus grapsus (Linnaeus, 1758)
Common name: Red Rock Crab
Other names: Sally Lightfoot crab
French name: Graspe peint, Sally-pied-léger (common name shared with another species: Percnon gibbesi), Crabe Zagaya, Graspe marbré, Crabe rouge de rocher, Crabe japonais.
Order: Decapoda
Family: Grapsidae
Size: Up to 7 cm for males and females.
Habitat : Rocky coasts, on rocks hit by the waves.
Food: Mainly algae and sometimes other plants. They can also consume molluscs, other crustaceans and dead animals.
Reproduction : Males fight face to face for females. After mating, females carry the fertilized eggs under their bodies. The larvae are released when they hatch. Females can store sperm in their spermatheca. They will only mate again when all that sperm has been used to fertilize more eggs.
Geographic area: Tropical and subtropical coasts of North and South America, both on the Pacific and Atlantic sides. American islands located in these same latitudes.

The Red Rock Crab has an almost circular and very flattened carapace.
The claws at the tip of the first pair of legs are small and symmetrical. The other pairs of legs are wide and flat and end in small curved spikes for clinging to rocks.
The colours are quite variable, rather dark brown to black for young crabs, reddish brown to grey spotted with light for adults.
The eyes are very spaced.