Moon Crab

• Its consumption of leaf litter and seedlings influences which trees manage to germinate, so that a crab shapes the composition of the forest.
• Its burrows aerate the soil and speed up nutrient recycling in the coastal forest.
• Although it lives on land, its larvae are marine: the females have to walk down to the shore to release them.
• Its colours give it its name: a jet-black carapace, legs of intense orange or red, and purple or yellow patches at the joints.
• It is terrestrial as an adult and lives in the forest, at times quite far from the sea, but it still depends on the ocean: the females make mass migrations to the shore to release their larvae.
• Its burrows aerate the soil, and its role as a detritivore matters: it consumes leaf litter and seedlings, and influences the composition of the coastal understorey vegetation.
• It shelters in its burrow by day and comes out at night in search of leaves, which it drags inside.
• The name Halloween crab comes precisely from the combination of black and orange.
• It is common in the coastal forests of Costa Rica and Panama, and its migrations are a well-known natural attraction.

Skeleton type

Invertebrate - chitin exoskeleton (crustacean)

Habitat and environment

Coastal rainforest of the Central American Pacific, within a few hundred metres of the sea

Sources consulted: Sherman, trabajos sobre Gecarcinus quadratus; Smithsonian Tropical Research Institute; Organización de Estudios Tropicales

Best time: The rainy season, when they migrate en masse towards the coast to release their larvae

The pins mark the parks and dive sites where its presence is documented.