Climbing ability of Microtus (Terricola) duodecimcostatus and M. (T.) gerbei

The behaviour and ability to climb of two fossorial rodents: Microtus (Terr icola) gerbei and M. (T.) duodecimcostatus were compared in a sintopic area in the Spanish Pyrenees. The climbing mode is very similar in both species and they are proficient climbers. The Pyrenean and Mediterranean pine vole s used their toe nails to climb a variety of surfaces and are able to climb mild slopes or surfaces with edges, similar to those covered with stones. Our findings are in disagreement with the general notion of the poor climbi ng ability of fossorial mammals. We suggest that this disagreement may aris e from the fact that climbing ability depends on several factors, including body size, digging mode and the practice. The effect of each of these fact ors on climbing ability is discussed.