Decoding dog communication through the physiology and behavior of urine marking

Although olfaction is the main sensory domain in dogs and urinary markings are crucial behavioral patterns involved in canids' communication, the scientific literature on this topic is quite scarce. In the present work, we investigated the relationship between male dogs marking behavior (scored throughout different facial expression, marking distance from the target odor etc.) and physiological response (urine concentrations of the hormones mainly involved in the physiological responses to social stressors: cortisol, oxytocin, adrenaline, testosterone; and the neurotransmitters most responsible for cognitive flexibility: norepinephrine and dopamine) to different emotional odors. Specifically, the odour stimuli were urine odors collected from (1) an unfamiliar female in estrus, which were expected to increase male dogs' arousal level due to sexual interest; and of (2) an unfamiliar intact male showing overt agonistic behaviors toward conspecific males, which were expected to elicit the arousal level in the tested subjects representing a potential threat. Although preliminarily, our data would indicate a relationship between differences in the type of marking behavior of male dogs and both hormonal and neurotransmitters levels in their urines, suggesting a modulation in canine cognitive strategy during marking.