Fiddler crabs get their name from the male's large claw. They use the claw to defend their burrows and to attract mates. Males have a highly ritualized combat of arm-waving, bobbing of the body, and standing with an open, upright stance. However combat rarely gets physical as there is too much risk of injury to both crabs. Ecological and Environmental Importance of Fiddler Crabs Fiddler crabs play important roles in many marsh processes.
Fiddler crabs are also avid burrowers.
Their activity can erode or undermine marshbanks. Their burrowing and feeding affect the aeration, and hence the growth of marsh grasses. They stimulate the turnover and mineralization of important nutrients. They are also a good environmental indicator and sensitive to environmental contaminates especially insecticides. Their population densities are an example of the high productivity of our vital wetlands.