Swimming ability of the Mediterranean pine vole Microtus [Terricola] duodecimcostatus

We studied the swimming capacity of the fossorial rodent Microtus (Terrícola) duo­decimcostatus fde Sélys-Longchamps, 1839), and found it to be a proficient swimmer in comparison with other fossorial species. We determined that main factor affecting swimming ability is the resistance of its hair to water absorption and its small body size. The hypothesis suggesting that insectivore moles are better swimmers than rodent mole is discussed. We find that body size, rather than the taxonomical group (insectivore or rodent), appears to be an important factor affecting swimming ability of fossorial species. The wide distribution of M. (7*.) duodecimcostatus could be partly explained by its high swimming ability; rivers, therefore, may not be significant geographical barriers to its dispersal.