Heikegani

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iHeikegani

Scientific classification

Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Decapoda
Suborder:	Pleocyemata
Infraorder:	Brachyura
Family:	Dorippidae
Genus:	Heikea
Species:	H. japonica

Binomial name

Heikea japonica
(von Siebold, 1824)

Heikegani (平家蟹, ヘイケガニ) is a species of crab native to Japan, with a shell that bears a pattern resembling a human face. It is locally believed that these crabs are reincarnations of the spirits of the Heike warriors defeated at the Battle of Dan-no-ura as told in the Heike Monogatari ("The Tale of the Heike"). The pattern of ridges on the carapace serves a very functional purpose as sites of muscle attachment. Similar patterns are found on species in many parts of the world, including fossilized remains.

Heikegani were used by Carl Sagan in his popular science television show Cosmos: A Personal Voyage erroneously as an example of unintentional artificial selection. The story goes that the crabs with shells resembling Samurai were thrown back, while those not resembling Samurai were eaten, giving the former a greater chance of reproducing. [1] However, the maximum width of adult heikegani crabs is only about 30 mm (1.2 inches), so fishermen throw these crabs back into the sea regardless of appearance.