Saturday, 24 May 2014

Fiddler Crab's Retreat

Fiddler crabs need to be afraid when the tide comes in.  In photo below a grapsid crab has not taken notice of the incoming tide and its legs are in the water.  It is in great danger as a banded toadfish (Sphaeroides pleurostictus) has seen it and is intent on making a meal of the crab.  Toadfish have teeth that easily cut through the shells of almost any crab.

toad fish hunting a crab - Sphaeroides pleurostictus
Toadfish hunting a crab
The best thing for a fiddler crab to do is hide in its hole. As an added measure, fiddler crabs also hide entrance to their holes. As the tide rises, the crabs know as their internal clocks tell them it is time to cut out a mud door and seal then entrance once they are inside their holes.

A fiddler crab making mud door
Uca dussumieri cutting a mud door
The video below shows a fiddler crab (Uca coarctata) making a door for its hole.

video

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