The communicating skills of dogs are well documented and especially their contact-seeking behaviours towards humans. The aim of this study was to use the unsolvable problem paradigm to investigate differences between breed groups in their contact-seeking behaviours towards their owner and a stranger. Twenty-four dogs of ancient breeds, 58 herding dogs, and 17 solitary hunting dogs were included in the study, and their behaviour when presented with an unsolvable problem task (UPT) was recorded for 3 min. All breed groups interacted with the test apparatus the same amount of time, but the herding dogs showed a longer gaze duration towards their owner compared to the other groups and they also preferred to interact with their owner instead of a stranger. Interestingly, the solitary hunting dogs were more in stranger proximity than the other groups, and they also showed a preference to make contact with a stranger instead of their owner. Hence, we found differences in contact-seeking behaviours, reflecting the dog-human relationship, between breed groups that might not only be related to their genetic similarity to wolves, but also due to the specific breeding history of the dogs.

Horses are commonly trained using negative reinforcement. However, a growing body of scientific evidence supports positive reinforcement as an efficient training method for horses. In this study we investigated the effects of adding a small but regular amount of positive reinforcement training to horses trained with negative reinforcement. A total of 36 privately owned horses not previously trained with positive reinforcement were divided into a training (N = 17) and a control (N = 19) group. The owners in the training group were asked to follow a training plan based on positive reinforcement for eight to nine weeks, in addition to their normal negative reinforcement training. The control horses continued with their usual negative reinforcement training. All horses were subjected to behavioural tests before and after the training period: a motionless human test to assess contact-seeking behaviour and a cognitive bias test to assess emotional state. Mane hair samples were obtained from all horses at the start and at the end of the training period to analyse hair cortisol concentrations as an expression of long-term stress. In addition, all owners filled out a questionnaire about their perceived relationship with their horses before and after the training period. We found that horses in the training group engaged in more physical contact (P = 0.050) with an unfamiliar person after the training period compared to before. The training group also tended to improve their owner-assessed relationship score (P = 0.072). They did not, however, show changes in their emotional state as assessed by the cognitive bias test (P > 0.1). Furthermore, we found no difference between the training and control groups in terms of hair cortisol concentrations. We conclude that a small but regular addition of positive reinforcement training can increase horses contact-seeking behaviour towards humans but is not enough to improve their emotional state or long-term stress levels.

Previously, we found that dogs belonging to the herding breed group, selected for human cooperation, synchronise their long-term stress levels with their owners. The aim of the current study was to investigate features that could influence long-term stress levels in ancient dog breeds, genetically closer to wolves, and dogs specifically selected to work independently of their owner. Twenty-four ancient breed dogs and 18 solitary hunting dogs were recruited and hair samples were obtained from both dogs and owners from which hair cortisol concentration (HCC) was analysed. Additionally, the owners completed lifestyle surveys, the Monash Dog Owner Relationship Scale (MDORS) on human-dog relationship, and both dog and owner personality questionnaires (Dog Personality questionnaire and Big Five Inventory survey). The results from the MDORS indicate that the subscale Perceived cost correlated to the dog HCC of tested breed groups: solitary hunting breeds (chi (2)=4.95, P=0.026, beta =0.055), ancient breeds (chi (2)=2.74, P=0.098, beta =0.027), and herding dogs included from a previous study (chi (2)=6.82, P=0.009, beta=- 0.061). The HCC of the solitary hunting dogs was also related to the owner personality traits Agreeableness (chi (2)=12.30, P<0.001, <beta>=- 0.060) and Openness (chi (2)=9.56, P=0.002, beta =0.048) suggesting a more substantial influence of the owner on the solitary hunting dogs HCC compared to the ancient breeds. No effect of owner HCC on dog HCC was found in either ancient or in solitary hunting breeds. Hence, the long-term stress synchronisation is likely to be a trait in breeds selected for human cooperation. In conclusion, dog HCC is often related to the owners personality, but is primarily influenced by the owner-dog relationship.

Humans have shared a long history with horses and today we mainly consider horses as companions for sports and leisure activities. Previously, the human perspective of the human-horse relationship has been investigated but there has been little focus on the horses perspective. This study aimed to reveal whether horses show attachment-related behaviour towards the owner compared to a stranger in a modified Strange Situation Procedure (SSP) consisting of a walking phase, a standing still phase, separation from the owner/stranger and lastly a reuinon. We tested 26 privately owned horses in an indoor experimental area of 20 x 14 m. In addition to testing, the owners were asked questions about their training methods. Based on these questionnaire results, owners were divided into groups depending on whether they mainly used negative reinforcement, positive reinforcement or a combination of both methods during training. They also completed a horse personality questionnaire. The results showed that the horses spent more time in door proximity when separated from the owner and the stranger (owner: Z =-3.46, P = 0.001; stranger: Z = 3.40, P = 0.001) compared to the reunion phase, and they sought human proximity during reunion. The horses heart rates were higher during the separation compared to the reunion with both the owner (Z =-3.44, P = 0.001) and the stranger (Z =-2.40, P = 0.016). These results are examples of attachment-related features and suggest that horses consider both the owner and the stranger as a safe haven. However, the results are not clear as to whether or not horses perceive their owners as a secure base since their exploratory behaviour during owner reunion was similar to that during stranger reunion. Interestingly, horses trained with positive reinforcement spent most time in door proximity during separation from the stranger (chi(2)(2) = 6.18, P = 0.045) and similarly there was a tendency also during owner separation (chi 2(2) = 5.20, P = 0.074). The same group of horses also spent more time in stranger proximity (chi(2)(2) = 6.16, P = 0.046) and in physical contact with stranger (chi(2)(2) = 8.62, P = 0.013) than the other two training style groups during reunion. When correlating scores from the horse personality questionnaire with behaviours during owner reunion, we found few significant associations, but the trait Inquisitive correlated with both proximity to owner and ears forward (rs = 0.41, P = 0.035 and rs = 0.49, P = 0.011, respectively), and ears forward also correlated with the trait Excitability (rs = 0.39, P = 0.047) and Dominance (rs = 0.46, P = 0.019). Hence, this study revealed attachment-related behaviours of horses towards humans even though the results cannot resolve whether these fulfil all criteria for an attachment-bond.

Hair cortisol is a promising biomarker to measure long-term stress since cortisol is incorporated into the hair shaft as it grows. However, few studies have previously assessed hair cortisol concentrations (HCC) in horses. In this study, HCC was evaluated in both mane hair from the neck and body hair from the withers in 153 horses of different breeds, from seven different stables with three different management regimes (Free-roaming horses, Riding school horses, Trotter horses). In addition, 4 hours of behavioral observations were performed at each stable, and for 43 of the horses, a personality survey was completed. Mane and withers HCC correlated moderately, but significantly (r_s=0.48, p<0.001). Differences between the stables were found for both mane and withers hair (both p<0.01) and the stable with lowest HCC also showed highest occurrences of positive social and resting behaviors (both p<0.01). There were no significant differences in HCC between the management regimes even though Free-roaming horses showed less negative social behavior compared to Riding school horses (p=0.041) and Trotter horses (p=0.055). The personality traits Dominance, Anxiousness, and Excitability revealed weak to moderate correlations with mane HCC (r_s=-0.34, p=0.027; r_s=-0.46, p=0.002; r_s=-0.31, p=0.043 respectively) which might suggest that personality could also be related to long-term stress levels in horses.

Due to our long history of living in close association with horses, these animals are suggested to have enhanced skills in understanding and communicating with humans. Today, horses have become important to humans for sport and leisure and their understanding of human behaviour and their human-directed behaviour are therefore of great importance. In this study, we investigated 22 horses in a human contact-seeking experiment where they were presented with an unsolvable problem and a detour experiment with a human demonstrator. The unsolvable problem consisted of pieces of carrot in a closed bucket and the detour resembled the shape of V. Additionally, personality traits of the participating horses were assessed. Interestingly, the full-sized horses (N=11) showed more human-related behaviours when presented with an unsolvable problem compared to before the carrots were made unreachable (p=0.033), while the ponies (N=11) did not. However, neither the full-sized horses nor the ponies were significantly more successful in the detour after human demonstrations than in control trials. When comparing the two experiments, we found the task-oriented behaviour in the detour test to positively correlate with human proximity and eye contact-seeking behaviour towards humans during the unsolvable problem in the contact-seeking test. Interestingly, again this was only true for the full-sized horses (pamp;lt;0.05) and not for the ponies. From the horse personality questionnaire results, the traits excitability and anxiousness revealed strong negative correlations with human-directed behaviour in the contact-seeking experiment (pamp;lt;0.05). Hence, size (full-sized horse/pony) and personality influenced the human-related behaviours of the horses and we suggest a future focus on these aspects to deepen our understanding of human-horse communication.

This study reveals, for the first time, an interspecific synchronization in long-term stress levels. Previously, acute stress, has been shown to be highly contagious both among humans and between individuals of other species. Here, long-term stress synchronization in dogs and their owners was investigated. We studied 58 dog-human dyads and analyzed their hair cortisol concentrations (HCC) at two separate occasions, reflecting levels during previous summer and winter months. The personality traits of both dogs and their owners were determined through owner-completed Dog Personality Questionnaire (DPQ) and human Big Five Inventory (BFI) surveys. In addition, the dogs activity levels were continuously monitored with a remote cloud-based activity collar for one week. Shetland sheepdogs (N = 33) and border collies (N = 25), balanced for sex, participated, and both pet dogs and actively competing dogs (agility and obedience) were included to represent different lifestyles. The results showed significant interspecies correlations in long-term stress where human HCC from both summer and winter samplings correlated strongly with dog HCC (summer: N = 57, chi(2) = 23.697, P amp;lt; 0.001, beta = 0.235; winter: N = 55, chi(2) = 13.796, P amp;lt; 0.001, beta = 0.027). Interestingly, the dogs activity levels did not affect HCC, nor did the amount of training sessions per week, showing that the HCC levels were not related to general physical activity. Additionally, there was a seasonal effect in HCC. However, although dogs personalities had little effects on their HCC, the human personality traits neuroticism, conscientiousness, and openness significantly affected dog HCC. Hence, we suggest that dogs, to a great extent, mirror the stress level of their owners.

Dogs are known to excel in interspecific communication with humans and both communicate with humans and follow human communicative cues. Two tests commonly used to test these skills are, firstly, the problem-solving paradigm, and, secondly, following human referential signals, for example pointing. The aim of the present study was to investigate whether dogs that seek more human contact in an unsolvable problem-solving paradigm also better understand human communicative cues in a pointing test. We also assessed between- and within-breed variation in both tests. 167 dogs were tested and were of the breeds German shepherd dog and Labrador retriever. The Labradors were separated into the two selection lines: common type (bred for show and pet) and field type (bred for hunting). A principal component analysis of behaviours during the problem solving revealed four components: Passivity, Experimenter Contact, Owner Contact and Eye Contact. We analysed the effect of these components on success rate in the pointing test and we found no effect for three of them, while a negative correlation was found for Owner Contact (F(1,147) = 6.892; P = 0.010). This was only present in common-typed Labradors. We conclude that the ability to follow a pointing cue does not predict the propensity for human-directed social behaviour in a problem-solving situation and suggest that the two tests measure different aspects of human-directed social behaviour in dogs.

Humans have selectively bred and used dogs over a period of thousands of years, and more recently the dog has become an important model animal for studies in ethology, cognition and genetics. These broad interests warrant careful descriptions of the senses of dogs. Still there is little known about dog vision, especially what dogs can discriminate in different light conditions. We trained and tested whippets, pugs, and a Shetland sheepdog in a two-choice discrimination set-up and show that dogs can discriminate patterns with spatial frequencies between 5.5 and 19.5 cycle per degree (cpd) in the bright light condition (43 cd m(-2)). This is a higher spatial resolution than has been previously reported although the individual variation in our tests was large. Humans tested in the same set-up reached acuities corresponding to earlier studies, ranging between 32.1 and 44.2 cpd. In the dim light condition (0.0087 cd m(-2)) the acuity of dogs ranged between 1.8 and 3.5 cpd while in humans, between 5.9 and 9.9 cpd. Thus, humans make visual discrimination of objects from roughly a threefold distance compared to dogs in both bright and dim light.

The oxytocin system may play an important role in dog domestication from the wolf. Dogs have evolved unique human analogue social skills enabling them to communicate and cooperate efficiently with people. Genomic differences in the region surrounding the oxytocin receptor (OXTR) gene have previously been associated with variation in doge communicative skills. Here we have utilized the unsolvable problem paradigm to investigate the effects of oxytocin and OXTR polymorphisms on human-directed contact seeking behavior in 60 golden retriever dogs. Human-oriented behavior was quantified employing a previously defined unsolvable problem paradigm. Behaviors were tested twice in a repeated, counterbalanced design, where dogs received a nasal dose of either oxytocin or saline 45 min before each test occasion. Buccal DNA was analysed for genotype on three previously identified SNP-markers associated with OXTR. The same polymorphisms were also geno-typed in 21 wolf blood samples to explore potential genomic differences between the species. Results showed that oxytocin treatment decreased physical contact seeking with the experimenter and one of the three polymorphisms was associated with degree of physical contact seeking with the owner. Dogs with the AA-genotype at this locus increased owner physical contact seeking in response to oxytocin while the opposite effect was found in GG-genotype individuals. Hence, intranasal oxytocin treatment, an OXTR polymorphism and their interaction are associated with doge human-directed social skills, which can explain previously described breed differences in oxytocin response. Genotypic variation at the studied locus was also found in wolves indicating that it was present even at the start of dog domestication.

Unlike their wolf ancestors, dogs have unique social skills for communicating and cooperating with humans. Previously, significant heritabilities for human-directed social behaviors have been found in laboratory beagles. Here, a Genome-Wide Association Study identified two genomic regions associated with dog's human-directed social behaviors. We recorded the propensity of laboratory beagles, bred, kept and handled under standardized conditions, to initiate physical interactions with a human during an unsolvable problem-task, and 190 individuals were genotyped with an HD Canine SNP-chip. One genetic marker on chromosome 26 within the SEZ6L gene was significantly associated with time spent close to, and in physical contact with, the human. Two suggestive markers on chromosome 26, located within the ARVCF gene, were also associated with human contact seeking. Strikingly, four additional genes present in the same linkage blocks affect social abilities in humans, e.g., SEZ6L has been associated with autism and COMT affects aggression in adolescents with ADHD. This is, to our knowledge, the first genome-wide study presenting candidate genomic regions for dog sociability and inter-species communication. These results advance our understanding of dog domestication and raise the use of the dog as a novel model system for human social disorders.

It is challenging to measure long-term endocrine stress responses in animals. We investigated whether cortisol extracted from dog hair reflected the levels of activity and stress long-term, during weeks and months. Hair samples from in total 59 German shepherds were analysed. Samples for measuring cortisol concentrations were collected at three occasions and we complemented the data with individual scores from the Canine Behavioural Assessment and Research Questionnaire (C-BARQ). Generalised linear mixed model (GLMM) results showed that hair cortisol varied with season and lifestyle: competition dogs had higher levels than companion, and professional working dogs, and levels were higher in January than in May and September. In addition, a positive correlation was found between the cortisol levels and the C-BARQ score for stranger-directed aggression (r = 0.31, P = 0.036). Interestingly, the factor "playing often with the dog" (r = -0.34, P = 0.019) and "reward with a treat/toy when the dog behaves correctly" (r = -0.37, P = 0.010) correlated negatively with cortisol levels, suggesting that positive human interactions reduce stress. In conclusion, hair cortisol is a promising method for revealing the activity of the HPA-axis over a longer period of time, and human interactions influence the cortisol level in dogs.

Dogs were domesticated from wolves about 15,000 years ago, and an important selection pressure (intentional orunintentional) has been their ability to communicate and cooperate with people. They show extensive human-directedsociability, which varies within as well as between breeds and is not shared by ancestral wolves. Hence, dogs arepotentially ideal models for studying the genetics of social behavior. Here, we review some recent research carried outby us and others on this subject. We present results showing that recent selection of different breed types can be usedas a model system for investigating the genetic architecture of personalities. Furthermore, we review data showingthat human-directed social behavior is significantly related to a small number of genes that have known connectionsto human social disorders such as autism and schizophrenia. We suggest that dogs are excellent study subjects foranalyzing the evolution and genetics of social behavior and can serve as probes for human health and welfare.

There is a growing and important need for large-scale characterisation of dog behaviour, for example to conduct genetic analyses or to assess welfare. An extensive number of standardised tests and questionnaires are used for this, but few focus on the normal behaviour in situations which are frequently encountered in the everyday life of companion dogs. The aim of this study was to develop and validate a fast, but standardised method to characterise behavioural variation in pet dogs, based on a brief observation in a situation often encountered by many dogs, namely during training classes. The spontaneous behaviour of dogs was video-recorded during 3 minutes in a standardised setting, while their owners were occupied filling in a short questionnaire, and during 30 seconds of walking on leash. Behaviours, including contact seeking behaviour with both the owner, a stranger and other dogs, together with general activity and interaction with a novel object were later analysed and further processed in two separate Principal Component Analyses (PCA). The PCs from the two test parts correlated significantly with each other and aspects of both home and test environment influenced several components in both PCAs. Age and sex also showed significant effects on test outcome, e.g. age affected how social and explorative the dog was and females jumped more on their owner, whilst males pulled the leash more. In addition, dogs that were perceived as cooperative by their owner, looked more at their owner and pulled the leash less. In conclusion, this simple test captures essential parts of the normal, everyday behaviour profile of dogs, such as owner- and dog-directed social behaviour, which are not usually measured in the commonly used test batteries for dogs.

Through domestication and co-evolution with humans, dogs have developed abilities to attract human attention, e.g. in a manner of seeking assistance when faced with a problem solving task. The aims of this study were to investigate within breed variation in human-directed contact seeking in dogs and to estimate its genetic basis. To do this, 498 research beagles, bred and kept under standardized conditions, were tested in an unsolvable problem task. Contact seeking behaviours recorded included both eye contact and physical interactions. Behavioural data was summarized through a principal component analysis, resulting in four components: test interactions, social interactions, eye contact and physical contact. Females scored significantly higher on social interactions and physical contact and age had an effect on eye contact scores. Narrow sense heritabilities (h2) of the two largest components were estimated at 0.32 and 0.23 but were not significant for the last two components. These results show that within the studied dog population, behavioural variation in human-directed social behaviours was sex dependent and that the utilization of eye contact seeking increased with age and experience. Hence, heritability estimates indicate a significant genetic contribution to the variation found in human-directed social interactions, suggesting that social skills in dogs have a genetic basis, but can also be shaped and enhanced through individual experiences. This research gives the opportunity to further investigate the genetics behind dogs’ social skills, which could also play a significant part into research on human social disorders such as autism.

Domestication processes tend to release animals from natural selection and favour traits desired by humans, such as food-production and co-operative behaviour. A side effect of such selective breeding is the alteration of unintended traits. In this paper, we investigate how active selection for egg production in chickens has affected the visual system, in particular the optical sensitivity that relates to the ability of chickens to see in dim light. We measured eye dimensions as well as the pupil diameter at different light intensities (the steady state pupil dynamics), in adult male and female White Leghorns and the closest relatives to their ancestor, the Red Junglefowls. With this information, we calculated the focal length and optical sensitivity (f-number) of the eyes. Males have larger eyes than females in both breeds and White Leghorn eyes are larger than those of Red Junglefowls in both sexes. The steady state pupil dynamics is less variable, however, the combination of pupil dynamics and eye size gives a higher optical sensitivity in Red Junglefowl eyes than in White Leghorns at light intensities below approximately 10 cd/m². While eye size and focal length match the larger body size in White Leghorns compared to Red Junglefowls, the steady state pupil dynamics do not. The reason for this is likely to be that eye morphology and the neuro-muscular control of the pupil have been affected differently by the strong selection for egg production and the simultaneous release of the selection pressure for high performing vision. This study is the first description of how optical sensitivity has changed in a domesticated species and our results demonstrate important considerations regarding domestication processes and sensory ability.