Boy, these guys are tough to photograph; they're agile and fast as lightning. You'd be too if you were a tasty little pupu favored at luaus and graduation parties. This is the 'a 'ama crab, Grapsus tenuicrustatus, also known as the thin-shelled black crab, rock crab, or natal lightfoot crab. Like the nearly two-hundred types of crabs here in Hawaii, they are ten-leggers, with the front pair bearing stubby chelae, or claws. Their carapace is flattened, as are their legs, making it easier for them to slip into the cracks and crevices, and to flatten out against the rock when a big waves splashes in. Algae is what motivates them to brave the intertidal zone, but they'll scavenge as well, keeping the beach clean and tidy. It's not uncommon to find their reddish molted shells, which are this color because the chromatophores, or pigment-bearing cells are no longer alive, leaving the shell to reveal its natural coloration. People use an ahele to catch them, a V-shaped tool on the end of a long pole. Thin line connects the points of the V, and is used to snare the cautious but curious crabs by the eye stalks.
welcomes you to visit with the all the wonderful flora and fauna that we share this lovely aina with.