||Releasing and Directing Stimuli of Patrol/Marking||Page 25|
The releasing and directing stimuli of approach locomotion and stop-and-sniff may include not only visual and vibrissal stimuli, but also olfactory stimuli coming from the scent glands of conspecifics. This may explain why the motor patterns are so often directed towards the face (sniff-nose), ano-genital region (sniff-ano-genital region), or flanks (sniff-back) which are the regions of the body in which scent glands are highly developed in muroid rodents [Eisenberg, 1967; Lehman and Adams, 1977]. These particular patterns of social investigation have been described in M musculus, R norvegicus, and Me auratus [Grant and Mackintosh, 1963], R fuscipes [Barnett and Stewart, 1975], Mer unguiculatus [Swanson, 1974], and Mi pennsylvanicus [Turner and Iverson, 1973]. This may also help to explain why the locomotion of muroid rodents such as R norvegicus [Eibl-Eibesfeldt, 1953b; Telle, 1966] and M musculus [Eibl-Eibesfeldt, 1950] tends to be directed along specific "runs" marked by the urine of conspecifics.
The directing of approach locomotion may be influenced not only by analysis of immediate directing stimuli, but also by a synthesis involving learning and memory of previous social encounters. The fact that dominant males of M musculus locomote primarily along their territorial boundaries [Mackintosh, 1970] may reflect previous encounters with conspecifics along these boundaries. A similar explanation may be applied to the behavior of "passage-guarding" observed in territorial males of R norvegicus [Calhoun, 1962] and M musculus [Anderson and Hill, 1965].
The releasing of scent-marking motor patterns may also depend upon olfactory stimuli from pheromones. There is a tendency for animals to scent-mark the same object or location where others have scent-marked, a tendency that can lead to noticeable accumulations of scent-marking substance, such as the "urinating posts" of M musculus [Welch, 1953], the "gerbil hillocks" of Rh opimus [Naumov, 1975], or the marking sites of Mer unguiculatus [Roper and Polioudakis, 1977].