|A sand fiddler crab emerges from his burrow. Photographed at North Peninsula State Park, Florida.|
As fiddlers are affected by non-living components of environment, they too have an effect on it. They feed on detritus and parts of dead organisms that would be left behind as the tide retreats. Almost frantically, they use their one small claw to shovel bit after bit of mud into their bristly mouthparts where water pumped in from their gills separate food particles from sediment. Their digging oxygenates the sand and soil in the process making it richer and more productive. The idea that they only have the time during low tide to feed as much as they can might account for why they always appear to be in a rush to eat. They know when to get the job done, and don't waste a second. In fact, this biological clock, centered around the tidal cycles, is so engrained in some fiddler crabs that even when taken away from their natural environment they continue to follow it. When placed in an artificial environment with a controlled temperature and amount of light, the crabs still follow the movement of the tides. Fascinating little critters, am I right?
Castro, P., & Huber, M. E. (2010). Marine biology (8th ed.). New York: McGraw-Hill Higher Education.