ON THE ORIGIN AND COLONIZATION OF HOUSE MICE IN THE MADEIRA ISLANDS

The skulls and skins of adult house mice from the Madeira Islands have been studied and compared with those from the Salvage Islands and with material from the neighbouring Portuguese mainland man‐associated and wild forms, respectively Mus musclus domesticus Rutty, 1772 and M. sprelus Lataste, 1883. Differences between island and mainland populations were found in some of the analysed features. Insular skins of mice were found to be smaller than those of specimens from the mainland. However, in Madeiran and Salvage mice the toothrows were much more developed than in the mainland house mice. It is considered that the causes of these differences lie in the different characteristics of the habitats, mainly food availability, and also in the isolation of populations. Mus musculus domesticus appears to be the only form of the house mouse to have so far successfully colonized the Madeiras. Copyright © 1992, Wiley Blackwell. All rights reserved