Ground transport can be a stressful operation for dolphins if the long period of restraint causes damage to internal organs, especially to the lung, generated by their own weight. Buoyancy is deprived from dolphins under moist transport, in which dolphins are transported on mattresses. Upgrading mattresses is an effective way to modify the transportation method so as to compensate for the loss of buoyancy. In Indo-Pacific bottlenose dolphins (Tursiops aduncus), we tried to find mattresses that performed well at distributing the dolphins' weight and preserved their pulmonary function. When using EV-17 (thickness, 50 mm) put on EE-20 (thickness, 50 mm), a wider support area, less extreme changes in pressure, and lower maximum pressures were observed compared with other mattress systems tested. On this mattress system, lower breathing rates, lower heart rates, and higher exhaled CO(2) concentrations were shown compared with using standard mattresses. These results suggest that the performance of the combination of EV-17 and EE-20 is better than that of the standard mattress in terms of the cardiopulmonary function of dolphins. Zoo Biol 27:331-340, 2008. (c) 2008 Wiley-Liss, Inc.