Calappa japonica
Shame-faced crabs are common crab species on the sandy floor of shallow seas. They look like round buns, with eight slender walking legs attached. Their broad flat chelipeds cover their “face” below the eyes, as if ashamed, which is the reason for their common name. Although slender, the power of their eight legs should not be underestimated. This crab may walk slowly but it is very efficient at digging in the sand. It only takes a few seconds for it to cover its round body with sand, leaving only its two small eyes exposed. Its two large chelipeds are close to its body, effectively keeping it from sinking too far into the sand. Moreover, do not be fooled by its seemingly harmless name and appearance. It does not eat a vegetarian diet. Anything it catches, regardless if alive or dead, becomes food. Their two large chelipeds exhibit typical dimorphic differentiation. On one, the teeth are thick and blunt and it is used to crush the hard shells of sea snails and shellfish, like a nutcracker. Along the edges of the other are sharp teeth that are like serrated blades used for cutting up prey. The surface of the carapace of the Japanese shame-faced crab is covered in button-like protrusions. It is speculated that they increase the strength of the carapace to resist attacks by predators.
