Crab
A crab is a decapod crustacean with a broad body, five pairs of legs, and a short abdomen folded underneath. Its first leg pair usually bears claws.
Decapoda: An order of crustaceans with five pairs of thoracic appendages, including shrimps, lobsters, and crabs. Crabs belong to this order, whose name means ten-footed.
Crab locomotion: The ways crabs move, including walking, swimming, climbing, and burrowing. Leg design and habitat shape the crab’s characteristic movement.
Crab fishery: The capture and management of crabs for commercial, subsistence, or recreational use. Crab harvest connects the animal’s biology to livelihoods and resource management.
Hermit crab: A decapod crustacean with a soft, curled abdomen usually protected inside an empty shell. Despite its name, it is not a true crab and lacks the crab’s compact abdomen.
Keystone species: A species whose ecological effects are disproportionately large relative to its abundance. Some crabs strongly influence prey populations and habitat structure.
Crustacean: An arthropod with a chitinous exoskeleton, jointed limbs, and usually two pairs of antennae. Crabs are crustaceans with the group’s defining arthropod features.
Crab molting: The growth cycle in which a crab sheds its exoskeleton and expands before the new shell hardens. This is the crab-specific form of the arthropod molt.
Crab aquaculture: The farming of crabs in controlled or managed aquatic environments. Farming attempts to meet demand while managing wild-stock pressure.
Lobster: A decapod crustacean with an elongated body, prominent tail, and usually large claws. Lobsters share the decapod order but retain a long, muscular abdomen.
Mangrove ecosystem: A coastal ecosystem dominated by salt-tolerant trees growing in sheltered tropical and subtropical waters. Mangrove crabs recycle nutrients and help shape sediment and plant communities.