Swimming ability of the European fossorial vole Microtus (T.) gerbei underdifferent laboratory conditions

We studied the swimming ability of the fossorial rodent Microtus (Terricola ) gerbei. This rodent was not as proficient in swimming as the other two sy mpatric species in the Spanish Pyrenees (M. lusitanicus and M. duodecimcost atus). However, swimming time of M. gerbei was within the range expected fo r other fossorial and subterranean species. Sex was not significant to swim ming time. Even though hair became soaked significantly faster in males tha n in females, and males were significantly heavier than females, these diff erences appeared nor to affect significantly their swimming performance. We determined that the main factor affecting the swimming ability of M. gerbe i is its having thick water-resistant fur. The hair of this rodent took lon ger to wet in cold than in temperate water, which suggests that this mole-v ole is better adapted to swimming in cooler waters.