Ecology and Geology of the Queensland Coast
(was MangroveCreatures - see post index below)
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.
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.
Uca dussumieri cutting a mud door
The video below shows a fiddler crab (Uca coarctata) making a door for its hole.