Heikegani in Cosmos by Carl Sagan

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 as an example of unintentional artificial selection. However, some experts have questioned this. 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 some fishermen throw these crabs back into the sea regardless of appearance. But smaller specimens may have been eaten in the past, before mass fishing. It is difficult to know for sure how much of the crab's shape and quantity has been dictated by artificial selection. (Wikipedia)

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• heikegani
• crab
• cosmos
• carl
• sagan

[fatmeteor]

The text describing this video suggests that Sagan "erroneoously" used the crab as an example, meaning that Sagan was in error. Is this what the poster meant?

[newgusita]

I've updated the information which source was always from wikipedia.. now it says "some experts have questioned this"... for me the story itself is fascinating beyond the scientific issues

[mrzisme]

@ ByronC900

Dont make retarded arguments, no one wants to be like Iran, and if you ask anyone outside of the United States, they dont wanna be the bullies of the world like the US is either. Watch "confessions of an economic hitman", then come back here and make an intelligent response about whats goin on in Iraq, and potentially soon to be Iran.

[sierpinskigasket]

Note the way Sagan pauses before he says "other favours"

[SovietWarMachine42]

@PtAltmVansanTarr not necessarily. I believe that most of them would, with all the wars going on at the time, know what a soldier looked like without requiring paintings.

[MarianoRyu]

Hmm, weren't the right names the Taira (Heike) and the Minamoto (Genji)?

[PtAltmVansanTarr]

Sagan made a mistake here, in coming from a world in which images have been proliferated everywhere. In order for the artificial selection to have worked the way he says, all the lower class people would have had to have the same access to paintings and illustrations as the 1st world middle class has today

[PtAltmVansanTarr]

No way, I don't believe that fishermen did this because they would have had to have seen masks or paintings which weren't accessible to the lower-class fishermen

[deeppurple28]

1 Year worth of college in under 8 minutes!

[Jukeboxheroswsprod]

6:44 lol baby crabs



[cjdjtmwt]

平家♂BOY

[chihatsu]

"Selling flowers and... other favors" had me laughing.

[ubergossen]

@newgusita mm hm, the article saying that the crab was not artificially selected was pretty compelling, I just read it. Basically, other crabs have been found in different parts of the world with almost the same back pattern, which is the shell forming over certain muscles giving it that shape. And also like you said, that the crabs are too small to be eaten. Too bad cause this would be a great example of artificial selection.

But science is all about questioning things and sometimes being wrong