COMPARATIVE STUDIES ON WATER METABOLISM OF BATS (RHINOPOMA, RHINOLOPHUS AND MYOTIS)

1. Unlike bats from temperate regions, Rhinopoma hardwickei can live without drinking water. 2. The metabolism of Rhinopoma is slower than that of Rhinolophus, although both have almost the same weight. Rhinopoma needs less food and consequently consumes less oxygen and produces less heat and water by oxidation. 3. The daily water consume of Rhinolophus is very high (11,7 cm3 daily maximum) and varies from individual to individual and from day to day. 4. The kidney of Rhinolophus is bigger and has a bigger number of glomeruli. The kidney of Rhinopoma has a longer papilla renis. 5. In spite of its shorter papilla renis the urine of Rhinolophus is not less concentrated than that of Rhinopoma under normal conditions. 6. The concentration of urea in the blood of bats is 4-5 times as high as that in human blood. 7. Rhinopoma has an extremely short gut. The passage through the gut is very slow. The excrements of both Rhinopoma and Rhinolophus have the same water content. 8. The insensible perspiration of Myotis and Rhinolophus is much higher than that of Rhinopoma, this difference becomes bigger with higher temperatures. Rhinopoma perspires relatively more through its lungs whereas Rhinolophus and Myotis do so more through their skin. 9. The chemical analysis of the skins of Rhinopoma and Myotis showed almost no content of mucopolysaccharides. The retention of water cannot be herewith explained. 10. The skin of Myotis and Rhinolophus is highly capillarized whereas the skin of Rhinopoma has relatively few capillaries. 11. Body temperature of Rhinopoma was never lower than the ambient temperature. The ability of Rhinopoma to regulate its body temperature is very limited. © 1969 Springer-Verlag.