Japanese spider crab
Macrocheira kaempferi
— Where the name comes from
Macrocheira is “long-handed”, from makrós and cheír: an adult male’s front legs, outstretched, span almost four metres. The epithet remembers Engelbert Kaempfer, the German physician who spent two years in Japan at the end of the seventeenth century, when the country was closed to foreigners, and brought back to Europe its first serious natural history.
— Facts
- Group
- Crustaceans · Malacostraca · Maxillopoda
- Order
- Crabs, lobsters and shrimps
- Habitat
- Bottoms between 150 and 600 metres; rises to 50 to breed
- Range
- Japanese waters, from Honshu to Kyushu
- Size
- Carapace 40 cm; leg span up to 3.8 metres
- Diet
- Molluscs, carrion, bottom algae
- Lifespan
- Estimated up to 100 years
— Characteristics
- 01
It is the living arthropod with the greatest limb span.
- 02
The legs are very slender and break easily: many adults have lost some.
- 03
It walks slowly on the bottom and never swims.
— What sets it apart
It is the most extensive arthropod alive today, and the reason there are none larger lies in how these animals grow: the outer shell has to be replaced, and every moult is a moment when the body, without support, must hold itself up. Beyond a certain size weight wins. In open water it is so fragile that a great many adults walk on seven legs, or six, regrowing the missing ones at each moult. Since it stops moulting as an adult, an old individual carries decades of encrustation, sponges and scars: its shell is an archive.
