The red-jointed fiddler crab is the most common and widespread fiddler crab in the Bay region
You can identify a fiddler crab species by examining its enlarged claw: the sand fiddler crab’s claw is smooth on the underside. If the claw is not smooth on the underside and had red joints, it is a red-jointed fiddler crab. Otherwise, it is a marsh fiddler crab.
Fiddler crabs breathe oxygen from the atmosphere.
The male’s enlarged major claw is not for fighting predators, but primarily to attract a mate and discourage rivals.
If a male loses its major claw, the remaining claw grows to the same size as the lost claw. The new claw that grows becomes the smaller claw.
Although the male’s major claw is large, fiddler crabs are not especially dangerous to handle. But be careful – the claws can break off easily.