Anatomy of the nasal passages of three species of Australian bats in relation to water loss

A previous study found substantial variation in rates of water loss in three species of Australian bats, with the orange leafnosed bat (Rhinonycteris aurantius) having a rate more than twice that of the large bentwing bat (Miniopterus schreibersii) and the ghost bat (Macroderma gigas). Using histological sections, we examined the nasal passages of these species to determine whether any of the species have complex turbinals that may function to reduce respiratory water loss. M. schreibersii has the most complex nasal passages, and R. aurantius has the simplest. Calculations indicate that the respiratory water loss of R. aurantius and M. schreibersii are similar, but this indicates that the nasal turbinals of M. schreibersii function to conserve pulmonary water given that the metabolic rate, and therefore respiratory frequency, is higher in M. schreibersii. R. aurantius and M. gigas echolocate by emitting pulses from the nostrils whereas M. schreibersii emits pulses from the mouth. The structure of the nasal passages of nasal emitters is constrained by the demands of echolocation, and this may preclude the development of complex turbinal arrangements required for the conservation of respiratory water. � CSIRO 2007.