SWIMMING ABILITY OF THE MEDITERRANEAN PINE VOLE MICROTUS (TERRICOLA) DUODECIMCOSTATUS

We studied the swimming capacity of the fossorial rodent Microtus (Ter ricola) duodecimocostatus (de Selys-Longchamps, 1839), and found it to be a proficient swimmer in comparison with other fossorial species. W e determined that main factor affecting swimming ability is the resist ance of its hair to water absorption and its small body size. The hypo thesis suggesting that insectivore moles are better swimmers than rode nt mole is discussed. We find that body size, rather than the taxonomi cal group (insectivore or rodent), appears to be an important factor a ffecting swimming ability of fossorial species. The wide distribution of M. (T.) duodecimcostatus could be partly explained by its high swim ming ability; rivers, therefore, may not be significant geographical b arriers to its dispersal.