Coat Color in Wild Populations of the Roof Rat in Hawaii

Abstract

Rattus rattus rattus has occupied the Hawaiian Islands not longer than 188 years. Three coat color mutants are present and were probably introduced with the original colonizing stocks. Four principal populations are discerned from mapping of phenotype frequencies. It is postulated that coat colors by themselves are of neutral selective value, and that their present distributional pattern has arisen through pleiotropic action of the coat color genes whose major adaptive significance in local environments is physiological.