Species differences in urine scent-marking and counter-marking in Peromyscus.

Species comparisons indicate that scent-marking may differ as a function of mating system and co-housing with the opposite sex ("pairing"). We previously demonstrated that pairing may decrease male solicitation to unfamiliar females in the monogamous Peromyscus californicus but not in the non-monogamous P. leucopus. Whether urine scent-marking of females changes following pairing and whether scent-marking of paired males varies in response to scent-marks of their cagemate versus those of an unfamiliar female has not been examined. Therefore, we tested P. californicus and P. leucopus for within and between species differences in urine scent-marking of: 1) paired and non-paired females in an unscented arena, and 2) paired males in response to their female cagemate's or an unfamiliar female's scent-marks (counter-marking). Consistent with previous findings, P. californicus of both sexes deposited more urine scent-marks and covered greater surface area than P. leucopus. In both species, female scent-marking did not differ according to pairing status and male counter-marking did not differ in response to the scent-marks of their female cagemate versus an unfamiliar female. More females of both species and more P. leucopus, but not P. californicus, males scent-marked more around the perimeter than centrally. Potential explanations for these findings are discussed.