Why do fiddler crabs have exoskeleton?

The exoskeleton provides a strong, protective barrier against predators and environmental hazards. It helps protect the crab's soft body from physical damage, such as being crushed or pierced.

Support and shape:

The exoskeleton provides structural support and maintains the crab's shape. It helps the crab maintain its posture, move its limbs, and perform various activities.

Muscle attachment:

The exoskeleton serves as attachment points for muscles. Muscles are connected to the inner surface of the exoskeleton, allowing the crab to move and manipulate its body parts.

Water conservation:

Crabs are susceptible to water loss due to their high surface-area-to-volume ratio and the presence of gills for respiration. The exoskeleton helps reduce water loss by preventing excessive evaporation.

Sensing:

Some parts of the exoskeleton, such as antennae and setae, are specialized for sensory functions. They contain sensory receptors that help the crab detect changes in the environment, including touch, smell, and taste.

Communication:

Fiddler crabs use their enlarged claws, which are covered by the exoskeleton, for communication and display during mating and territorial interactions. The waving of these claws can convey signals to other crabs and play an important role in their social behavior.