Scent matching modulates space use and agonistic behaviour between male snow voles, Chionomys nivalis

The 'scent-matching' hypothesis predicts that competitors could identify resource holders by investigating scent marks from a given area and matching these with the owner's odour when they meet. Previous studies on small rodents have supported the use of scent matching among males with mutually exclusive ranges. We designed an experiment to evaluate the potential role of scent matching in the snow vole, a species in which males have largely overlapping ranges but individually use specific locations within shared areas. Initial exploration of enclosures containing a choice between a scent-marked and an unmarked area established that males were more attracted to recently occupied areas. During a subsequent social encounter with either the donor of the scent marks present in the enclosure (matching opponent) or another male (nonmatching opponent), males were less aggressive towards matching than nonmatching opponents. Furthermore, during exploration of enclosures after encounters, males spent significantly less time at the scent-marked side after meeting a matching male but not after meeting another male. These results suggest that male snow voles may use scent matching to identify potential opponents and to respond differentially to occupied areas. By modifying their behaviour after assessing the identity of their opponents, males may be able to minimize current and prospective costly encounters with resource holders. Our findings show that the mechanism of scent matching is also compatible with spatial systems in which competing conspecifics possess overlapping ranges. (C) 2001 The Association for the Study of Animal Behaviour.