Behavioral and cardiac responses by dogs to physical human–dog contact

Measures of behavioral responses and cardiovascular parameters to evaluate and assess animal well-being are well established. A major aspect of companion animal well-being seems to originate from direct human–animal interaction. For pet dogs, the manner in which they obtain and respond to petting and hugs could interfere with the development of a pleasant human–dog companionship. Therefore, the purpose of this study was to evaluate cardiovascular responses by dogs to physical human–dog contact and to assess these physiological responses in relation to the dogs' behavioral responses. Noninvasive measurements of privately owned dogs' (N = 28) cardiovascular parameters and behavioral responses were carried out during 9 physical human–dog interactions (e.g., petting the dog on its back, holding a forepaw of the dog). The behavioral responses were grouped in categories, for example, redirected behavior, displacement activity, and appeasement gesture. The mean heart rate (HR) and 2 cardiac activity parameters, standard deviation of normal-to-normal R–R intervals (SDNN) and root mean square of successive heartbeat interval differences/SDNN (RMSSD/SDNN) ratio, differed significantly among the human–dog interactions. Petting and holding the dog around the head was associated with an increased SDNN. An increased vagal tone was the dogs' responses to being petted at the chest. Displacement activities correlated negatively with all cardiovascular parameters (HR, SDNN, RMSSD, and RMSSD/SDNN ratio). Appeasement gestures were positively correlated with HR and occurred less under an increased vagal tone. The behavioral strategies, that is, freezing (standing motionless with all legs on the floor) and withdrawal (moving backward without any agonistic display) were negatively associated with the cardiac activity parameters, RMSSD and RMSSD/SDNN ratio. The dogs' behavioral and physiological responses suggest that some common physical human–dog interactions perceived as unpleasant by dogs. Emphasis on human signaling in human–dog interactions encourages development of recommendations for pleasant and safe human–dog contact to enhance dogs' well-being and the human–dog relationship.