Japanese spider crabs

The Japanese giant spider crab (Macrocheira kaempferi) is a species of marine crab and is the largest crab found in the waters around Japan. At around 3.75 metres (12.3 ft), it has the largest leg-span of any arthropod. The Japanese name for this species is taka-ashi-gani, (Japanese: 高脚蟹; タカアシガニ), literally translating to "tall-legged crab". It goes through three main larval stages along with a prezoeal stage to grow to its full size.

The Japanese giant spider crab is the sole living member of the genus Macrocheira. Three fossil species of this genus are known: M. ginzanensis and M. yabei from the Miocene of Japan, and M. teglandi from the Oligocene. They are sought by crab fisheries, and are considered a delicacy in Japan. To prevent overexploitation from harming the species, conservation efforts have been put in place to protect them and their population from overfishing.