Oxytocin modulates responses to inequity in dogs

Although several animals respond negatively to inequity, the underlying neurochemistry of the process remains poorly understood. In this study, we tested whether the neuropeptide oxytocin mediates responses to inequitable outcomes in domestic dogs (Canis familiaris). Subjects exchanged tokens to receive a food reward in conditions in which the distribution of reward varied. Dogs did respond negatively to inequity, refusing to participate in the test when their partner was rewarded and they were not. Their responses could not be explained merely by frustration, since the presence of a partner being rewarded had a significant effect on their behavior, compared to when the partner was present but not rewarded. Furthermore, after oxytocin intake dogs were less sensitive to the inequitable distribution of reward, performing more successful trials than when administered with placebo. Further, oxytocin treatment also increased dogs’ attention towards their partners, and slowed their decision times, but did not affect their affiliation level toward their partners or the experimenter. Together, our findings suggest that oxytocin modulates responses to inequity in dogs by potentially affecting decision-making processes, but not by increasing affiliation

Dog breed differences in visual communication with humans

Domestic dogs (Canis familiaris) have developed a close relationship with humans through the process of domestication. In human-dog interactions, eye contact is a key element of relationship initiation and maintenance. Previous studies have suggested that canine ability to produce human-directed communicative signals is influenced by domestication history, from wolves to dogs, as well as by recent breed selection for particular working purposes. To test the genetic basis for such abilities in purebred dogs, we examined gazing behavior towards humans using two types of behavioral experiments: the `visual contact task' and the `unsolvable task'. A total of 125 dogs participated in the study. Based on the genetic relatedness among breeds subjects were classified into five breed groups: Ancient, Herding, Hunting, Retriever-Mastiff and Working). We found that it took longer time for Ancient breeds to make an eye-contact with humans, and that they gazed at humans for shorter periods of time than any other breed group in the unsolvable situation. Our findings suggest that spontaneous gaze behavior towards humans is associated with genetic similarity to wolves rather than with recent selective pressure to create particular working breeds

Familiarity bias and physiological responses in contagious yawning by dogs support link to empathy

In humans, the susceptibility to yawn contagion has been theoretically and empirically related to our capacity for empathy. Because of its relevance to evolutionary biology, this phenomenon has been the focus of recent investigations in nonhuman species. In line with the empathic hypothesis, contagious yawning has been shown to correlate with the level of social attachment in several primate species. Domestic dogs (Canis familiaris) have also shown the ability to yawn contagiously. To date, however, the social modulation of dog contagious yawning has received contradictory support and alternative explanations (i.e., yawn as a mild distress response) could explain positive evidence. The present study aims to replicate contagious yawning in dogs and to discriminate between the two possible mediating mechanisms (i.e., empathic vs. distress related response). Twenty-five dogs observed familiar (dog’s owner) and unfamiliar human models (experimenter) acting out a yawn or control mouth movements. Concurrent physiological measures (heart rate) were additionally monitored for twenty-one of the subjects. The occurrence of yawn contagion was significantly higher during the yawning condition than during the control mouth movements. Furthermore, the dogs yawned more frequently when watching the familiar model than the unfamiliar one demonstrating that the contagiousness of yawning in dogs correlated with the level of emotional proximity. Moreover, subjects’ heart rate did not differ among conditions suggesting that the phenomenon of contagious yawning in dogs is unrelated to stressful events. Our findings are consistent with the view that contagious yawning is modulated by affective components of the behavior and may indicate that rudimentary forms of empathy could be present in domesticated dogs

Genetic dissection of behavioral traits related to successful training of drug detection dogs

Abstract Drug detection dogs play integral roles in society. However, the interplay between their behaviors and genetic characteristics underlying their performance remains uninvestigated. Herein, more than 120,000 genetic variants were evaluated in 326 German Shepherd or Labrador Retriever dogs to profile the genetic traits associated with various behavioral traits related to the successful training of drug detection dogs. Behavioral breed differences were observed in ‘friendliness to humans’ and ‘tolerance to dogs.’ A genome-wide association study within both breeds identified 11 regions potentially associated with drug detection dog characteristics as well as ‘interest in the target’ and ‘friendliness to humans,’ which are related to drug detection abilities. Among them, 63 protein-coding genes, including Atat1 and Pfn2 known to be associated with anxiety-related or exploration behavior in mice, respectively, were located surrounding the identified candidate polymorphisms. This study highlights genetic characteristics associated with behavioral traits that are important for the successful training of drug detection dogs. Thus, these findings may facilitate improved breeding and training of these dogs

Variables in the best GLMM explaining the occurrence of yawn contagion.

<p><i>ß</i>: Coefficient; SE: Standard error; CI: Confidence Interval.</p

Data from: Effect of canine oxytocin receptor gene polymorphism on the successful training of drug detection dogs

Drug detection dogs can be trained to locate various prohibited drugs with targeted odors, and they play an important role in interdiction of drug smuggling in human society. Recent studies provide the interesting hypothesis that the oxytocin system serves as a biological basis for co-evolution between dogs and humans. Here, we offer the new possibility that genetic variation of the canine oxytocin receptor (OXTR) gene may regulate the success of a dog’s training to become a drug detection dog. A total of 340 Labrador Retriever dogs that were trained to be drug detection dogs in Japan were analyzed. We genotyped an exonic SNP (rs8679682) in the OXTR gene and compared the training success rate of dogs with different genotypes. We also asked dog trainers in the training facility to evaluate subjective personality assessment scores for each dog, and examined how each dog’s training success was related to those scores. A significant effect of the OXTR genotype on the success of the dogs’ training was found, with a higher proportion of dogs carrying the C allele (T/C and C/C genotypes) being successful candidates than dogs carrying the T/T genotype. Dog personality scores of Training Focus (Factor 1) were positively correlated with an increased likelihood that a dog would successfully complete training. Although the molecular mechanism of the OXTR gene and its functional pathway related to dog behavior remains unknown, our findings suggest that canine OXTR gene variants may regulate individual differences between dogs in their responsiveness to training for drug detection

Mean (in seconds) of the behavioral variables according to the different breed groups.

<p>Standard deviation is shown in parentheses.</p

Breed and breed group sample size (<i>N</i>), sex (F: female, M: male), and mean age (years) of dogs tested in the present study.

<p>Breed and breed group sample size (<i>N</i>), sex (F: female, M: male), and mean age (years) of dogs tested in the present study.</p