Scent-Marking Behaviour in a Pack of Free-Ranging Domestic Dogs

Most mammals scent-mark, and a variety of hypotheses have been put forward to explain this behaviour. Most of our knowledge about scent marking in domestic dogs comes from studies carried out on laboratory or companion dogs, while few studies have been carried out on free-ranging dogs. Here, we explored the functional significance of different scentmarking behavioural patterns in a pack of free-ranging domestic dogs by testing two non-exclusive hypotheses: the indirect territorial defence and the dominance/threat hypotheses. Through direct observation, we recorded the locations of dog scent marks (urination, defecation and ground scratching) and information regarding the identity and posture of the marking animal. We found evidence that markings are used by dogs to form a ‘property line’ and to threaten rivals during agonistic conflicts. Both males and females utilized scent marking to assert dominance and probably to relocate food or maintain possession over it. Raised-leg urination and ground scratching probably play a role in olfactory and visual communication in both males and females. Urinations released by females, especially through flexed-leg posture, may also convey information about their reproductive state. Finally, our observations suggest that defecation does not play an essential role in olfactory communication among free-ranging dogs and that standing and squat postures are associated with normal excretion. Our results suggest that many of the proposed functions of marking behaviours are not mutually exclusive, and all should be explored through detailed field and laboratory studies.