Genetically-Determined Variation of Pelage Color and Reflectance in Natural and Laboratory Populations of the Marsupial Sminthopsis-Crassicaudata (Gould)

Abstract

A study of variation in dorsal pelage colour and reflectance of the dasyurid marsupial, Sminthopsis crassicaudata, has been based on animals captured from widely scattered areas in south-central Australia, and on a laboratory colony of this species. Measurements on the degree of resemblance between relatives gave heritability estimates of pelage reflectance close to the theoretical upper limit of unity. Measurements on the reflectance of animals captured from the wild revealed a geographical cline, with reflectance decreasing (animals becoming darker) with increasing southerly latitude. The higher reflectance (paler coloured) animals were found to inhabit the northern desert areas. We suggest that this cline results from a selective advantage enjoyed by animals whose dorsal pelage colour makes them relatively inconspicuous in their habitat to nocturnal preditors.