EN
The number, topographic sequence and duration of the moults of the coat of Mus musculus Linnaeus, 1758 are analysed using wild specimens from collections and albino specimens born and kept in the laboratory. Mice undergo an uninterrupted series of regular moults throughout its life. Each has a typical duration. The juvenile moult is the fastest and in all cases the speed of moulting is unconstant. At first the rate is accelerated but it frequently decelerates, and even pauses, so that some parts of the body, mainly the cephalic area, do not moult. This pause leads to a superposition of waves of different moults with the coexistence of 3 or more coats. The superpositions, revealed by dying the laboratory animals' coats, could be the reason why previous authors have claimed the existence of irregular moults in M. musculus. With the wild specimens, despite the fact that the inner surface of the skin yields less information, moulting patterns, similar to those described in the laboratory specimens, may be detected.