The burrowing behaviour of the toad Bufo viridis was studied in the laboratory on soil containing 11-13% moisture. These toads usually excavate shallow, temporary burrows from which they emerge intermittently. Time spent subsurface increases with rising ambient temperature in the range of 18-30° C. In these conditions, water loss is effectively reduced and a new water balance is achieved. On return to water access, after two months on soil, the toads rapidly regain only that amount of water lost previously. It is concluded that this temperature-sensitive burrowing behaviour is an important factor in these animals' successful survival in semi-arid conditions.