The Semaphore Crab

The semaphore crab is the most abundant crab that is found within the mangrove roots that lie close to creeks and water sources. Semaphore crabs have structural and behavioural adaptations that are influenced by tidal movement and tidal inundation. For instance, when the tide rises, the crab has taught itself to cover their hole with an air bubble that blocks the movement of water into their home. So when the tide goes back out, the air bubble is removed and they leave to gather nutrients that had been placed near their habitat by the rising water levels. In which, another behavioural adaptation that assists the crab in survival is the food they eat. As the crabs are deposit feeders; they feed on deritus which includes dead plants and animals which had been deposited onto the sediment when the tide gets low.