Here's why:
* Feeding: Fiddler crabs are primarily scavengers and feed on algae, detritus, and other small organisms they find on the mudflats and beaches. They need to be out of the water to find their food.
* Mating: Male fiddler crabs have one large claw that they use to attract females and to fight off other males. This courtship and fighting behavior happens on land.
* Nesting: Female fiddler crabs dig burrows in the sand or mud above the high tide line. They lay their eggs in these burrows, where they are safe from predators and the tides.
While fiddler crabs are well-adapted to life on land, they still need to be near water. They need access to the water to breathe and to keep their gills moist. They also need the water to wash away their waste products.