Fiddler Crab

by T. Takayama


First fiddler crab is Decapoda class sand crab family Uca arcuata. Fiddler crab`s gap length is from 20mm to 40mm there is a difference between variety sort of fiddler crab, gap width is 35mm. Eyestalk have a compound eye. It is long. Orbit of the eye grow too. Typically from the left and right eye is the center. Shell has an inverted trapezoid. The body color is red but sometimes difficult to determine the mud wearing colors easily.

Fiddler crab look over in over a large area while stand eyestalk in the case of fiddler crab live on the surface of the earth.


Second, fiddler crabs lives in tidal flats and mud hardened area. But human activity become a major threat, has reduced the habitat. Fiddler crab live in the seashore around the mouth of a river in the tropical zone and the subtropics. There is a liking for bottom material by each kind. Fiddler crab live in various place such as a beach at ebb tide, mangrove , a sandy beach and boulder.

Next, Ministry of the Environment published Red date list in 2000, had been semi-endangered species were unique and endangered in 2006 due to revision of the increased risk of extinction.

Given name

Next fiddler crab is named “taucchogane and ganetsukegani, magani” in the coast of Ariake sea.fiddler crab are caught with “ariakegani and yamatoosagani”.

Same group

Finally there is a white line fiddler crab. Gap width is 18mm. White line fiddler crab is smaller than fiddler crab. White line fiddler crab lives in a sandy beach and boulder. White line there are far more White line fiddler crab`s habitat than fiddler crab.


  1. 自分と同じ生物をしらべていた。


  2. I knew fiddler crab lives in tidal flats and they have inventions to be there.
    Also I Knew fiddler crab is decreasing now. I think that we shoud protect them.


  3. I think fiddler crab’s famous point is big claw. but this sentence little say. I ‘m little regrettable.


  4. I think Fiddler Crab is one of the creature that be exposed dangerous when I read your article.
    This article shows clearly that wahat is Fiddler Crab, where they live, what is their character.


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