Publication details

Is water really a barrier for the house mouse? A comparative study of two mouse subspecies



Type Article in Periodical
Magazine / Source Folia Zoologica
MU Faculty or unit

Faculty of Science

Field Zoology
Keywords dispersal; Mus musculus domesticus; M. m. musculus; swimming; water barrier
Description House mice are believed to be, unlike rats, only reluctant swimmers. If water is a barrier to mouse dispersal water bodies and streams can have a substantial impact on the genetic structure of populations. Previous studies revealed influence of rivers on the position and structure of the European hybrid zone between two house mouse subspecies, Mus musculus musculus and M m. domesticus. In this study, we used a simple motivation experiment to test the disposition of both wild and inbred mice representing the subspecies to overcome a water barrier. As the more dispersing sex, males were chosen for the experiment. Mice were tested under two air/water temperature regimes, 20 degrees C and 10 degrees C. Contrary to a common belief tested animals entered water rather easily, often even engaging in repeated swimming. We found significant differences in scored behavioural parameters between the subspecies. Under the 20 degrees C regime, both wild and inbred domesticus males entered and crossed the water earlier and more often swam even when satiated. Strikingly, under the 10 degrees C regime, the results were rather equivocal but with the opposite tendencies, with musculus males being more willing to swim. We discuss implications of these findings for the hybrid zone dynamics.