Looking around tidal mud banks will often be rewarded with a sighting of these interesting and showy crabs.

Orange footed fiddler crab - Uca coarctata near the Daintree ferry - Photo by Alex Pawlow

The enlarged claw is used as a dominance display and in fighting other males. It is also used to attract the females in a "waving display".

If the large claw is lost in a fight, the crab will develop a new one on the opposite side on its next malt. It will also be able to regenerate other legs on a new malt.

They actually use the smaller claw for feeding, which they do by moving mud to their mouth parts and filtering the organic matter from the mineral material.

This method of feeding actually gives the Fiddler crab its common name. The appearance of the small claw continually moving backwards and forwards looks like someone moving a bow across a violin.

The female fiddler crabs claws are of the same size. The females can carry thousands of eggs in her abdomen (when they are often referred to as a sponge crab). At the right stage the mother will enter the water where the eggs hatch as free swimming larvae. They remain in the water until they hatch to a true crab stage and then return to land.