The Semaphore Crab is the most abundant crab found in mangroves and estuaries, and usually lives among the mangrove roots.
The Semaphore Crab is easily identified by its mottled purple carapace and eyes on the end of long stalks. Juveniles have orange claws while the claws of adults are purple.
The Semaphore Crab lives in intertidal mangroves.
The Semaphore Crab is found from Brisbane in Queensland, New South Wales to Port Philip Bay in Victoria, and eastern Tasmania.
Other behaviours and adaptations
The word 'semaphore' means a type of signalling apparatus with moving arms or flags, and refers to the males' habit of standing by their burrows and signalling to other crabs by waving their claws up and down. Exactly what they are signalling is unclear. Perhaps they are trying to grab the attention of females by showing off their large claws, or they may be warning other males to stay out of their territory.