Crab Facts

About the crab

Crabs are not one natural group. The crab body shape has evolved several separate times from the basic decapod plan, a process called carcinisation, so the true crabs and groups like hermit crabs arrived at it independently. Sizes run from the pea crab, only a few millimeters across, to the Japanese spider crab, whose legs can span up to 4 m (13 ft). Many like hiding in rocky cracks.

Plenty of crabs live free in the sea and eat almost anything, while others stick to plants or meat, and some are parasites. A good number have moved into fresh water or other habitats away from the sea. People eat a lot of them: crabs make up about 20% of marine crustaceans caught or farmed for food. Dressed crab is a classic British seafood dish, and crab curry is common in Goa and Mozambique.

Did you know?

• The astrological sign Cancer is a crab, and crabs also appear in Malay and Greek myths.
• Hermit crabs are popular pets and aquarium animals.
• A popular joke says everything evolves into crabs, though that idea is not accurate.