Heikegani
Encyclopedia
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
native to Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, with a shell that bears a pattern resembling a human face. It is locally believed that these crabs are reincarnation
Reincarnation
Reincarnation best describes the concept where the soul or spirit, after the death of the body, is believed to return to live in a new human body, or, in some traditions, either as a human being, animal or plant...
s of the spirits of the Heike warriors defeated at the Battle of Dan-no-ura
Battle of Dan-no-ura
The ' was a major sea battle of the Genpei War, occurring at Dan-no-ura, in the Shimonoseki Strait off the southern tip of Honshū. On March 24, 1185, the Genji clan fleet, led by Minamoto no Yoshitsune, defeated the Heike clan fleet, during a half-day engagement.The Taira were outnumbered, but...
as told in The Tale of the Heike
The Tale of the Heike
is an epic account of the struggle between the Taira and Minamoto clans for control of Japan at the end of the 12th century in the Genpei War...
.
Heikegani were used by Carl Sagan
Carl Sagan
Carl Edward Sagan was an American astronomer, astrophysicist, cosmologist, author, science popularizer and science communicator in astronomy and natural sciences. He published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books...
in his popular science television show Cosmos: A Personal Voyage
Cosmos: A Personal Voyage
Cosmos: A Personal Voyage is a thirteen-part television series written by Carl Sagan, Ann Druyan, and Steven Soter, with Sagan as presenter. It was executive-produced by Adrian Malone, produced by David Kennard, Geoffrey Haines-Stiles and Gregory Andorfer, and directed by the producers, David...
as an example of unintentional artificial selection
Artificial selection
Artificial selection describes intentional breeding for certain traits, or combination of traits. The term was utilized by Charles Darwin in contrast to natural selection, in which the differential reproduction of organisms with certain traits is attributed to improved survival or reproductive...
, an interpretation published by Julian Huxley
Julian Huxley
Sir Julian Sorell Huxley FRS was an English evolutionary biologist, humanist and internationalist. He was a proponent of natural selection, and a leading figure in the mid-twentieth century evolutionary synthesis...
in 1952. According to this hypothesis, the crabs with shells resembling Samurai were thrown back to the sea by the fishers on respect to the Heike warriors, while those not resembling Samurai were eaten, giving the former a greater chance of reproducing. Thus, the more closely the crabs resemble a samurai face, the more likely they would be spared and thrown back.
This idea has met with some skepticism, as noted by Joel H. Martin. As humans don't use Heikegani for food, Martin posits that there is no artificial pressure favoring face-like shell patterns, contrary to Sagan's implication. The pattern of ridges on the carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
serves a very functional purpose as sites of muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
attachment. Similar patterns are found on species in many parts of the world, including fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
remains.