Chinese Mitten Crab

This species' distinguishing features are the dense patches of dark setae (the "fur") on its claws. The crab's body is the size of a human palm, and the legs are about twice as long as the 3–10-centimeter (1–4 in) wide carapace.

The Chinese mitten crab originates from Hong Kong to the border of Korea. It can be found inland, but prefers coastal areas. In the Yangtze, the largest river in its native range, Chinese mitten crabs have been recorded up to 1,400 km (760 nmi) upstream. It is known to settle in rice fields by the sea and rivers inland. The crab is found in both subtropical and temperate regions.

Chinese mitten crabs spend most of their lives in fresh water and return to the sea to breed (catadromous). Spawning crabs average around 5.5 cm (2+1⁄4 in) in length. In late August, sexual instincts awaken and they begin migrating downstream to the sea, away from their feeding grounds. During this migration, the crabs reach puberty and develop their sex organs. The crabs begin to breed in the brackish waters in late fall. The males arrive first and stay in the brackish waters all winter; the females arrive after. The eggs are laid within 24 hours of mating, then attached to the abdomen of the female. After the eggs are attached, the female leaves immediately, heading to the mouth of the river. The larvae hatch from the eggs during the summer, after which they float and drift about the brackish waters.

Crabs are an autumnal delicacy in Shanghai cuisine and eastern China. They are prized for the female crab roe, which ripens in the ninth lunar month and the males in the 10th. The crab meat is believed by traditional Chinese medicine practitioners to have a "cooling" (yin) effect on the body.

Crabs from Yangcheng Lake are especially prized, since they are perceived to have sweeter meat. Most of the Yangcheng crabs are exported to Shanghai, Hong Kong, and high-profit foreign markets. Responding to the spread of the crab to the West, businessmen have started seeing it as a new source of crab for the Chinese market. One proposed scheme involves importing unwanted crabs from Europe, where they are seen as a pest, to replenish local pure-bred stock.