Melanism

Selection for melanism and for low reproductive rate in Trichosurus vulpecula (Marsupialia).

Agouti grey pelage, as found in the opossum and many other mammals, is a generalised concealing coloration. In dense vegetation melanic pelage also is concealing, but the melanic phase displaces the grey one in rain forests where, in the current absence of predation, selection is not for colour. This local dominance suggests close linkage of genes for melanism with ones for toleration of humidity.