| This study explores olfactory communication in pikas, small montane lagomorphs of western North America. Pikas of both sexes maintain individual territories. Scent marking involves cheek marking and the deposition of urine and feces (fecal piles). Both field and laboratory data were used to answer questions about the message content, context, and location of cheek marks and to test hypotheses related to the possible functions of cheek marking by pikas.;Pikas cheek mark at a high rate during the breeding season and males mark (7.84 marks/hour) more than females (4.28). The net effect of pika spatial organization, space use, and mark locations, is that olfactory deposits are concentrated in potential mates' territories, resulting in olfactory familiarity during the breeding season. Laboratory data supported a mating-facilitation function of marking. Females are more likely to mate with males whose odors are familiar.;The distribution of cheek marks also was studied. The density of marks (marks per square meter) forms concentric rings of decreasing density outward from the center of an individual's territory. There is a pocket of high mark density in the regions of overlap with neighbor's territories. These densities may correspond to probabilities of chasing an intruding pika, and thus might serve a confidence-enhancement function. The possibility that cheek marking may be important in territorial maintenance also was studied. There is some evidence for this hypothesis, but it was not possible to draw a definitive conclusion.;Elimination marking was examined and an association was found between the locations of fecal piles and haypiles. Thus fecal piles may serve to demarcate a haypile.;The results of laboratory experiments showed that pikas can discriminate individual odors. In addition males can discriminate male versus female cheek-gland odors but females do not show a differential response, although they may have this discriminatory ability.;Olfactory communication in pikas plays an integral role in the social biology of the species. Individual and sex differences in odors may be important in pairwise spatial organization which, in turn, facilitates olfactory familiarity between potential mates. Females prefer to mate with these males whose odors are familiar. |
