Urine marking in male domestic dogs: honest or dishonest?

Abstract

Scent marking is a common mode of communication in mammals. Such marking is thought to communicate information about the signaler's size and corresponding competitive ability and accurately reflect the signaler's attributes (i.e., an honest signal). However, new data suggest that scent marking can be dishonest in certain circumstances. Via two studies, we tested the hypothesis that urine marking is a dishonest signal in adult male domestic dogs, which raise a hindlimb when marking vertical objects. In Study 1, we tested whether raised-leg angle (i.e., during a urination, the angle between a dog's raised leg and the axis normal to the ground) is a proxy for urine mark height (n = 15 dogs) and, in Study 2, we tested whether small dogs exhibit larger raised-leg angles than large dogs (n = 45 dogs). We videotaped urinations of adult male dogs and, afterwards, measured height of urine marks (Study 1) and degree of raised-leg angles (Studies 1 and 2). In Study 1, we found significant positive relationships between both raised-leg angle and height of urine mark and body size (using either body mass or height at withers) and height of urine mark; raised-leg angle was a stronger predictor than either measure of body size. In Study 2, we found a significant negative relationship between body size (using either body mass or height at withers) and average raised-leg angle. Our findings support raisedleg angle as a proxy for urine mark height and provide additional evidence that scent marking can be dishonest. Assuming body size is a proxy for competitive ability, small adult male dogs may place urine marks higher, relative to their own body size, than larger adult male dogs to exaggerate their competitive ability. We did not control for over marking, which also may explain our findings.

Can Dogs Limbo? Dogs’ Perception of Affordances for Negotiating an Opening

“…The results speak to dogs' perception of their body size with respect to their environment. This suggests that dogs not only perceive others' body sizes, as previously found [21,22,24], but also their own. The dogs in this study used knowledge of their body size when judging whether they would fit through an opening: the latency for subjects to reach an aperture they could easily fit through was significantly shorter than to one which was almost too small to fit through.…”

“…Some research addresses a dog's understanding of their body size with respect to the size of other dogs. Dogs self-handicap with smaller dogs in play [23] and small dogs perform higher raised-leg displays relative to their body size than large dogs do [24].…”

Encounters between pairs of unfamiliar dogs in a dog park

“…It can, however, also act as a display of dominance or social challenge among both wolves and dogs (Asa et al, 1990;Cafazzo et al, 2012). There is some evidence that scent marking can even indirectly communicate information like body size without direct interaction (McGuire & Bemis, 2017;McGuire et al, 2018).…”

Canine Olfaction: Physiology, Behavior, and Possibilities for Practical Applications

“…The marked object, such as a tree or a streetlamp, becomes a scent message containing much information about the individual who left it [ 65 ]. Adult males typically use the raised-leg posture, leaving an elevated mark, juvenile males use the lean-forward posture during which no hind limb is raised, and most females use the squat posture [ 69 ]. Male dogs and wolves mark more frequently in unfamiliar areas and will continue to do so even if their bladder is empty, implying that marking is not associated with urine passage [ 70 ].…”

“…Although wolves use feces for territorial marking [ 70 ], defecation is thought to play a less important role in communication in dogs [ 69 ]. However, when walked by an unfamiliar man, shelter dogs defecated less than when walked by an unfamiliar female [ 76 ].…”