The Samurai Crab

Myth-information about natural selection



A number of iconic examples have been used over the years to convince people of evolution’s supposed validity.2 Despite them having been soundly rebutted (some by evolution-believing scientists as well), certain prize horses in the evolutionary ‘stable of ideas’ still persist in textbooks and other evolutionary presentations.

Evolutionary claim:

“Superstitious Japanese do not eat Heike crab because its shell appears to be imprinted with the likeness of a medieval warrior.”

A lesser-known but quite sophisticated example has persisted in common evolutionary lore since 1952, when Julian Huxley (grandson of Charles Darwin’s ‘bulldog’, T.H. Huxley) published an article titled ‘Evolution’s copycats’.

His goal was to use an easily understood example of natural selection in action to explain its undoubted ability to cause creatures to adapt. Then he would extrapolate that idea to try and persuade his audience that all of life’s incredible design could be explained naturalistically.

The example came from a humble species of crab, Dorippe (now Heikea) japonica. Carl Sagan used this same example in his 1980 book (and TV show) Cosmos, which greatly boosted and popularized it.

Creepy carapace

These crustaceans have a pattern of grooves and ridges on their carapace that resembles the brooding face of a samurai warrior’s mask. This is why they are often called ‘samurai crabs’, and therein lies the intrigue of the illustration.

As the story goes, two feuding clans in Japan (the Genji or Minamoto, and the Heike) fought a great naval battle (Dan-no-ura) in 1185 that ended in decisive defeat for the Heike. According to legend, the ghosts of the warriors live on in their watery grave, transformed into crabs that bear the grotesque visage of an armoured samurai’s face.

Huxley’s original article in Life magazine describes how he believes these crabs came by such a striking feature:

The resemblance of Dorippe to an angry Japanese warrior is far too specific and far too detailed to be accidental: it is a specific adaptation which can only have been brought about by means of natural selection operating over centuries of time. It came about because those crabs with a more perfect resemblance to a warrior’s face were less frequently eaten than the others.3

The caption on a Heike crab picture in Huxley’s article reads:

Superstitious Japanese do not eat Heike crab because its shell appears to be imprinted with the likeness of a medieval warrior.

His argument was easy to grasp. When superstitious Japanese fisherman saw crabs with any likeness to a Samurai’s mask they threw them back but consumed the ones without them. This would benefit crabs with a ‘face’ and they would multiply, resulting in crabs with a more clearly ‘designed’ samurai mask over time.

As Carl Sagan put it in his Cosmos TV series:

How does it come about that the face of a warrior is cut on the carapace of a Japanese crab? How could it be? The answer seems to be that humans made this face.
If you’re a crab and your carapace is just ordinary, the humans are going to eat you, but if it looks a little bit like a face, they’ll throw you back and you’ll be able to have lots of nice little baby crabs that all look just like you.4

Natural selection is not evolution

Informed creationists reading this are likely yawning at this point. Organizations like CMI have demonstrated for years that natural selection,5although it can allow creatures to adapt within limits, does not cause the types of changes that could evolve anything in the particles-to-people sense.


“ The fishermen do not eat any of these crabs … All are thrown back.”

Natural selection is a process that selects from genetic information already available within the DNA of a creature; whereas evolution requires brand new genetic information for forms, functions, and features not currently in existence to arise de novo.6

So this example, even if true, would be no big deal anyway. But it is still influential among the uninformed. It is used to help evolutionists make the takeaway point that because this example of apparent design can be caused by selection, belief in God is not needed to explain any so-called design in nature after all. Design is an illusion caused by time, chance and circumstance. Huxley made this point by segueing from the crab example to many others, stating:

… there are plenty of other equally surprising examples of animals and or plants acquiring a protective resemblance to other animals or plants or to inanimate objects.7

Of course this is simply a deceptive debating tactic. You go from an example you claim has been observed to therefore ‘knowing’ of several other examples of this having happened (which weren’t observed at all, rather evolutionists presume that they happened that way).

The man-crab myth

But in any case, as evolutionist Joel W. Martin said in 1993 of this crab example:

Interesting reading, but it isn’t true.8

Martin should know. He is Associate Curator of Invertebrate Zoology at the Natural History Museum, Los Angeles, and his research centres on the life histories of decapod and branchiopod crustaceans. While his article still pays homage to evolution, he carefully rebuts the main elements of this crab story (which he calls a myth). For starters:

… it seems likely that the man-crab legend even precedes the date of the battle of Dan-no-ura, and was merely fitted to those events later … .

More importantly, he points out sound anatomical reasons for these features:

The grooves are external indications of supportive ridges, called apodemes, inside the crab’s carapace that serve as sites for muscle attachment. Elevated areas between these grooves allow for an increase in internal space, so that the various parts of a crab’s viscera—gastric, hepatic, cardiac, branchial, etc.—are reflected externally.

Not surprisingly, then:

… these ridges and grooves occur in nearly all members of the crab family Dorippidae, whether they live near Japan or not.

Martin even points out that some of these dorippid-type crabs are known from fossils, which evolutionists would have to concede predated the Samurai warrior caste. And then, what he calls “most damning to the myth” (bold emphases added):

… the fishermen who make their living from the Sea of Japan do not eat any of these crabs. Whether they resemble a samurai, a human face, or merely a crab is a moot point; all are thrown back. For Dorippe japonica reaches a maximum size of only 31 mm [1.2 in] across the back, not at all worth the trouble of retrieving from the nets, let alone sorting through to see which ones resemble a face and which do not.

With such a thorough refutation of all aspects of the myth, it is obvious to any fair-minded, objective assessment that the resemblance of the crab’s patterning to the mask is largely or wholly coincidental.


What about the confident assertions by these famous evolutionists that such distinct features ‘could only have been brought about’ in the way they described? They are seen as just that—assertions—confident storytelling not backed up by facts in the least. The facts have, rather, convincingly refuted them.

Beware what you accept as truth

It is easy to see how this example of ‘evolution in action’ came to be so popular. It is logical, has an interesting story attached and has historical details imbedded within it that give it a veneer of truth. But it is a fabrication (aside from the historical details about the battle of the two clans). And yet CMI has experienced skeptics at public presentations bring it up as supposed scientific ‘proof’ of evolution and a reason to deny the God of the Bible.

Why wasn’t this evolutionary storytelling exposed sooner? Perhaps it is because Huxley was introduced to his readers as an ‘eminent biologist’ and everyone assumed he would check his sources and wouldn’t resort to ‘storytelling’ as a scientist. (Much like lawyer-turned-geologist, Sir Charles Lyell wasn’t questioned on his dubious claims, about the age of Niagara Falls for example, because he was a British ‘gentleman’.)9

Once again, an evolutionary icon has been consigned to the garbage heap, but continues to rear its head. Unfortunately, it will likely keep doing so for many years to come, spurred on by an ideology that desires to deny the existence of God by denying Him the glory of creation.

References and notes

  1. Samurai crab (Heikea japonica). This crab is native to Japan, where it is known as the Samurai crab or Heikegani, and lives at a depth of 30 to 100 meters. Return to text.
  2. A search of will quickly reveal these, and their refutation: peppered moths, ‘horse evolution’, vestigial organs (especially the appendix), junk DNA, 98% chimp-human DNA similarity, Haeckel’s embryos, and more. Return to text.
  3. Huxley, J.S., Evolution’s copycats, Life, pp. 67–76, 30 June 1952. Return to text.
  4. Sagan, C, Cosmos, episode 2: ‘Heike Crabs’; Return to text.
  5. Despite the ‘human choice’, this is not artificial selection in the same sense as breeders consciously trying to effect changes—which is in any case completely analogous to natural selection. Return to text.
  6. So the issue then becomes a separate discussion, of whether mutations can supply the new information required—see Return to text.
  7. Huxley, Ref. 3, p. 70. Return to text.
  8. Martin, J.W., The Samurai Crab, Terra 31(4):30–34, 1993; all the other quotes from Martin reflect this source. Return to text.
  9. Pierce, L., Niagara Falls and the Bible; Return to text.

Helpful Resources

Readers’ comments

James K.
In nature many things including the human eye and bamboo shoot growth patterns are fractal in shape/design. This extreme homoplasy can only be attributed to the signature of the common Creator, evoking common ancestry is farcical.
Thomas C.
Intelligence is required for a choice to be made on the basis of wanted results or better results. Intelligence is not a characteristic or part of the definition of chance. So in this case what humans decided was better caused the shift in populations of crabs. The more desirable, i.e. larger food source is an earmark of intelligent choices. Intelligent selection. If we claim ‘nature’ selects for better survivability, then intelligence and predetermined purpose are ascribed to nature.
Jonathan Sarfati
The point of the article was that the human selection theory is a myth. But even if true, this hypothesized artificial selection would have reduced the information content of the population, not increased it, just like natural selection.

The term ‘natural selection’ has never been intended to imply that nature literally selects; it is a synonym for differential reproduction. See The fact of natural selection.

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