The Japanese spider crab, Macrocheira kaempferi, is a species of marine crab that lives in the waters around Japan. It has the largest leg span of any arthropod, reaching up to 3.8 metres (12 ft 6 in) and weighing up to 41 pounds (19 kg). It is the subject of small-scale fishery.
The Japanese spider crab has the greatest leg span of any arthropod, reaching 3.8 metres (12 ft 6 in) from claw to claw. The body may grow to a size of 40 centimetres or 16 in (carapace width) and the whole crab can weigh up to 41 pounds (19 kg). It is the males which have the longest chelipeds; females have much shorter chelipeds, which are shorter than the following pair of legs. Apart from its outstanding size, the Japanese spider crab differs from other crabs in a number of ways. The first pleopods of males are unusually twisted, and its larvae appear primitive. The crab is orange, with white spots along the legs. It is reported to have a gentle disposition "in spite of its ferocious appearance".
Japanese spider crabs are mostly found off the southern coasts of the Japanese island of Honshū, from Tokyo Bay to Kagoshima Prefecture. Outlying populations have been found in Iwate Prefecture and off Su-ao...