BEHAVIORAL-RESPONSES TO SCENT MARKS OF INCREASING AGE IN KLIPSPRINGEROREOTRAGUS-OREOTRAGUS

Klipspringers Oreotragus oreotragus are small antelopes which use scen t marks to demarcate and defend their territory. The strength of behav ioural response to the introduction of unfamiliar scent was measured i n order to estimate the effective lifespan of scent secretion. The tot al number of scent marks deposited during the experiment was higher th an control levels when fresh scent was introduced, but not when older scent was introduced. However, the proportion of marks deposited on in troduced twigs remained higher than control levels until scent was age d at least 7 d. The probability of licking twigs immediately before sc ent-marking was much higher than control levels when scent aged up to 3 d was introduced, but not when scent was aged 7 d or more. These res ults indicate that preorbital gland scent retains at least some degree of efficacy for up to 7 d. The decreasing level of response to scent aged 0-7 d is most likely to be due to decay of the scent signal. Howe ver, in contrast to the total number of marks deposited and the probab ility of licking before scent-marking, which both consistently decreas ed in response to older scent, the proportion of marks deposited on sc ent aged 3 d was higher than over fresh scent. It is suggested that, i n view of the role that scent-marking plays in territory defence, this difference in the timing of peak response between the three variables may represent an adaptive response to the perceived threat of encount er with an adversary, which is mediated by the age of the scent marks.