The Economic Consequences of Advertising Scent Mark Location on Territories

Abstract

The role of scent-marking in the maintenance of mammalian territories is well-documented (eg. Ralls, 1971; Brown and Macdonald, 1985; Gosling, 1982; Gosling and Roberts, in press). Scent marks are a form of status signal, advertising territory ownership, and recent evidence suggests they may also be condition-dependent signals of quality and competitive ability (Gosling et al., in press). In common with animal signals in other sensory modalities, scent marks thus provide a means of assessment which informs signal receivers about the signaller’s quality. Information about the location, density, freshness and chemical properties of scent marks are all likely to contribute to the appraisal of the signaller by the receiver before the participants meet. In a territorial context, the product of this appraisal may be a decision to avoid the risk of meeting the signaller by withdrawing from the territory, for example, if the signaller appears to be of far higher competitive ability. Alternatively, a receiver may defer a decision until it has more information, or until an opportunity arises to check this information in a face-to-face situation. Since scent mark detection often occurs in the signaller’s absence, receivers may need to confirm the identity of any opponent as the resource-holder before deciding on their next move. This can be achieved by comparing the odour of the marks with that of their opponent, a process known as scent-matching (Gosling, 1982,1990;Gosling and McKay, 1990). A positive match, which unambiguously confirms the owner’s status, may be sufficient to settle the contest conventionally and scent-marking thus helps to reduce the costs of territory defence (Gosling, 1986; Stenstrom 1998).