As they burrow deep into the mud of these marshes, the crabs collectively create a maze of tunnels which directly affect the growth of marsh grasses through aeration. Keeping marsh grasses from dying is an important part of maintaining an entire wetland ecosystem. Although small, these fiddler crabs play a vital role in the preservation of one of our most endangered ecosystems - wetlands. The fiddler crabs use their small claw to feed. Fiddler crabs are capable of scraping food particles off grains of sand.
Fiddler crabs turn a dark color during the day and turn a lighter color at night.
Most commonly seen crab in a salt marsh. Males have one large claw and one small claw. Both claws of the females are the same size. Males wave their claws to challenge other males to fight. During high tide, the fiddler crab packs sand into the entrance to his burrow and waits until the tides goes down again.