On the Workings of Some Crabs on the Sandy Beach of Western Sundarban, Bengal Delta, India

The present study includes the nature of burrowing and grazing activities of different types of Crabs on the beach floor of a part of shore line delta complex of Western Sundarbans, West Bengal, India (Fig. 1) along with their geological significance. Two species of the crab Ocypoda are seen forming contrasting burrows, pellets and grazing marks. One crab species with its products of burrowing activities significantly reflects microenvironment in its spatial extent with respect to the shoreline region. Such features might enable us to determine the orientation of shoreline and the basin marginal configuration of the past. Two species of the hermit crab Diogenes are located on the wave washed part of the foreshore and they form contrasting trails of grazing marks from which the orientation of the shoreline, foreshore slope and outer extremities of foreshore may be confidently indicated.