5 Colonies of the Orange Horseshoe Bat, Rhinonycteris-Aurantius (Chiroptera, Hipposideridae), in the Northern-Territory

Abstract

Five colonies of Rhinonycteris aurantius in the Northern Territory are described. Colonies occurred in caves and mine shafts and ranged in size from 40 individuals to about 11 250. In all, 24 000 R. aurantius were estimated to be present in the five colonies. Macroderrna gigas, Miniopterus schreibersii and Hippossideros after frequently occurred in the same caves and mine shafts as R. auranfius but only H. ater shared the same roost. Most R. aurantius used roasts between 30 and 32°C with relative humidities from 90 to 96%. Roosts were frequently in confined spaces and, as the bats roost 12 cm apart, were comparatively large. Male R. aurantius were significantly heavier than females (mean weight of males 8.4 g; mean weight of females 7.6 g; P<O.01) and there were marked regional differences in pelage colour. No breeding activity was observed and no juveniles were identified.