Scent-marking

Abstract

First paragraph: The scent marks of rodents have been cast as an olfactory equivalent of the elaborate and colorful train of the peacock (Pavo cristatus; Penn and Potts 1998a). This is a helpful analogy, illustrating the importance of scent marking in rodent sexual selection. Just as peahens prefer males with the showiest trains and gain fitness benefits through mating with them (Petrie et al. 1991; Petrie 1994), so female rodents use scent marks of males when choosing mates (as, indeed, do females of many other mammals). However, the analogy tells only part of the story, for scent marking is also inextricably linked with competition over resources and mating opportunities, usually between males. In this sense, scent marking resembles, for example, the roars of red deer stags (Cervus elaphus; Clutton-Brock and Albon 1979; Clutton-Brock et al. 1979), on the basis of which potential combatants assess their relative competitive ability and decide whether to challenge an opponent physically. In rodents, as in most mammals, scent marking is a means by which individuals assess the competitive ability of opponents (Gosling 1982, 1990; Gosling and Roberts 2001a). This may occur remotely, before an encounter occurs, or in conjunction with further assessment face to face. While there is variability in, and some debate about, the mechanisms involved, there is little doubt that scent marking is a fundamental component of territorial behavior and of advertising dominance status within social hierarchies.