Scent Marking in Mice: Open Field Test
This exercise is the second of the two experiments dealing with communication via scent marks in mice. In this Open-field Test, we observe scent marking behavior of male mice in response to presence or absence of urine stimuli in their environment. (In fact, the “open field” arena is enclosed and covered.)
Where mice live undisturbed for some time, their urine marks accumulate and are spread over most surfaces. At topographical edges such as walls, pipes, or rafters, posts of concentrated urine pile up over time. Dominant adult males mark very frequently. This advertises their aggressive dominance over other resident and intruder males. Dominant males overmark other males’ urine marks, while marks by dominant males are merely investigated by others. Dominant male marks guide dominant and subordinate males to stay within their territory and to avoid areas marked by other dominant males (Hurst 1990a). Juveniles use urine marks to stay within their parental territory.
Dominant males mark differently from subordinate males: they cover an entire area, while subordinates urine-mark along the walls of their enclosure or cage, and in fewer and larger patches. These patterns can be visualized under ultraviolet light (Desjardins et al. 1973).