The Soldier Crab lives in sandy estuaries and mangroves, and occurs in massive groups that seem to emerge from nowhere all at the same time.
The Soldier Crab is quite distinctive with its small, round, blue body on long jointed legs with purple stripes. As it marches around feeding, it moulds the sand into numerous pellets, sorting through it for organic matter. There is only one other species of soldier crab common in Sydney. This is the smaller Mictyris platycheles.
Soldier Crabs live on intertidal mangroves, beaches and estuaries.
Soldier Crabs are found from Northern Queensland, New South Wales, to Wilsons Promontory in Victoria. Also, western Indian Ocean to French Polynesia.
Other behaviours and adaptations
It is thought that the spontaneous arrival of Soldier Crabs is triggered by the falling tide. If disturbed, they burrow into the sand with a corkscrew motion, disappearing as quickly as they arrived.