‘Bat Erosion’ at Niah Great Caves

Abstract

AT the Great Caves of Niah, Sarawak, West Borneo¹, there is a relatively soft coral limestone of Miocene date in which these vertical cavities are common, and as in Trinidad², found where there are no stalactites. On the other hand, the rock in these places is damp and there may often be a ring of very slowly forming drips around the mouth of a cavity. Moreover, only small family groups of Miniopterus witkampi regularly use these sites as roosts, rarely more than five at once, hanging in a bunch from the top-dead-centre³. It is doubtful whether the scrabbling action of these small bats could ever excavate such cavities, and indeed the remarkable symmetry and the vertical axis of each formation suggests that it is due to solution rather than the activity of bats.