Behavioral differences among breeds of domestic dogs (Canis lupus familiaris): Current status of the science

Behavioural differences and similarities between dog breeds: proposing an ecologically valid approach for canine behavioural research

The behaviour of dogs holds great relevance for not only scientists from fundamental and applied research areas, but also due to the widespread roles of dogs in our societies as companions and working animals; their behaviour is also an important factor in animal and human welfare. A large proportion of dogs currently under human supervision belong to one of roughly 400 recognised breeds. Dog breeds can be characterised by distinctive, predictable and reproducible features, including some of their behavioural traits. To the scientist, the comparative analysis of the behaviour of dog breeds provides an opportunity for investigating an array of intriguing phenomena within an easily accessible model organism created from natural and human-driven evolutionary processes. There are many ways to design and conduct breed-related behavioural investigations, but such endeavours should always be based around biologically relevant research questions and lead to ecologically valid conclusions. In this review, we surveyed recent research efforts that included dog behaviour-related comparisons and applied a critical evaluation according to their methods of breed choice and the subsequent research design. Our aim was to assess whether these two fundamentally important components of experimental design provide a solid basis to reach valid conclusions. Based on 97 publications that fulfilled our selection criteria, we identified three primary methods used by researchers to select breeds for their investigations: (i) convenience sampling; (ii) hypothesis-driven, ancestry-based sampling; and (iii) hypothesis-driven, functional sampling. By using the SWOT (Strengths, Weaknesses, Opportunities, Threats) evaluation system, we highlight each of these techniques' merits and shortcomings. We identify when particular methods may be inherently unable to produce biologically meaningful results due to a mismatch between breed choice and the initial research goals. We hope that our evaluation will help researchers adopt best practices in experimental design regarding future dog breed comparisons.

Transposons in the Williams-Beuren Syndrome Critical Region are Associated with Social Behavior in Assistance Dogs

A strong signature of selection in the domestic dog genome is found in a five-megabase region of chromosome six in which four structural variants derived from transposons have previously been associated with human-oriented social behavior, such as attentional bias to social stimuli and social interest in strangers. To explore these genetic associations in more phenotypic detail-as well as their role in training success in a specialized assistance dog program-we genotyped 1001 assistance dogs from Canine Companions for Independence®, including both successful graduates and dogs released from the training program for behaviors incompatible with their working role. We collected phenotypes on each dog using puppy-raiser questionnaires, trainer questionnaires, and both cognitive and behavioral tests. Using Bayesian mixed models, we found strong associations (95% credibility intervals excluding zero) between genotypes and certain behavioral measures, including separation-related problems, aggression when challenged or corrected, and reactivity to other dogs. Furthermore, we found moderate differences in the genotypes of dogs who graduated versus those who did not; insertions in GTF2I showed the strongest association with training success (β = 0.23, CI95% = - 0.04, 0.49), translating to an odds-ratio of 1.25 for one insertion. Our results provide insight into the role of each of these four transposons in canine sociability and may inform breeding and training practices for working dog organizations. Furthermore, the observed importance of the gene GTF2I supports the emerging consensus that variation in GTF2I genotypes and expression have important consequences for social behavior broadly.

Risk factors for Echinococcus multilocularis intestinal infections in owned domestic dogs in a North American metropolis (Calgary, Alberta)

Human alveolar echinococcosis is increasingly documented in Alberta, Canada. Its causative agent, Echinococcus multilocularis (Em), can be transmitted to humans by infected dogs. We assessed the prevalence and associated risk factors for Em infections in domestic dogs in Calgary, Alberta, Canada. In this cross-sectional study that coupled collection and assessment of dog feces with a survey on potential risk factors, 13 of 696 (Bayesian true prevalence, 2.4%; 95% CrI: 1.3-4.0%) individual dogs' feces collected during August and September 2012 were qPCR positive for Em. Sequencing two of these cases indicated that both were from the same Em European strain responsible for human infections in Alberta. Likelihood of intestinal Em was 5.6-times higher in hounds than other breeds, 4.6-times higher in dogs leashed at dog parks than those allowed off-leash, 3.1-times higher in dogs often kept in the backyard during spring and summer months than those rarely in the yard, and 3.3-times higher in dogs living in neighbourhoods bordering Bowmont park than those in other areas of Calgary. This situation warrants surveillance of dog infections as a preventative measure to reduce infections in North America.

Association between the plasma concentration of melatonin and behavioral temperament in horses

Aggression in horses may cause serious accidents during riding and non-riding activities. Hence, predicting the temperament of horses is essential for selecting suitable horses and ensuring safety during the activity. In certain animals, such as hamsters, plasma melatonin concentrations have been correlated with aggressive behavior. However, whether this relationship applies to horses remains unclear. To address this research gap, this study aimed to evaluate differences in the plasma melatonin concentrations among horses of different breeds, ages, and sexes and examine the correlation between plasma melatonin concentrations and the temperament of the horses, including docility, affinity, dominance, and trainability. Blood samples from 32 horses were collected from the Horse Industry Complex Center of Jeonju Kijeon College. The docility, affinity, dominance, and trainability of the horses were assessed by three professional trainers who were well-acquainted with the horses. Plasma melatonin concentrations were measured using an enzyme-linked immunosorbent assay. The consequent values were compared between the horses of different breeds, ages, and sexes using a three-way analysis of variance and least significant difference post hoc test. Linear regression analysis was employed to identify the relationship between plasma melatonin concentrations and docility, affinity, dominance, and trainability. The results showed that the plasma melatonin concentrations significantly differed with breeds in Thoroughbred and cold-blooded horses. However, there were no differences in the plasma melatonin concentrations between the horse ages and sexes. Furthermore, plasma melatonin concentrations did not exhibit a significant correlation with the ranking of docility, affinity, dominance, and trainability.

Veterinary education and experience shape beliefs about dog breeds. Part 2: Trust

Dog breed stereotypes are frequently used to inform people's expectations about canine behavior, despite evidence that breed is largely uninformative in predicting individual dog behavior. Further, these beliefs differ among populations. However, it remains unknown how ratings of warmth toward a breed are associated with ratings of other social behavioral domains, and whether differences exist between populations with varying experience with dogs. The purpose of this study was to evaluate ratings of trust and warmth among survey respondents including veterinary students, veterinary faculty and staff, undergraduates in animal-health related majors and members of the general public. Using an online survey, respondents rated their likelihood to trust a dog in varying scenarios for 10 different dog breeds. Additionally, respondents used a feelings thermometer to rate how warm or cool they felt towards each breed. Findings revealed differences in feelings thermometer and trust ratings across populations. All ratings were lower among the veterinary academic respondents compared to the general public and undergraduates. Veterinary students further along in their training, as well as undergraduates with clinical experience, reflected perceptions similar to those of the veterinary faculty and staff providing support for cultural transmission of beliefs during veterinary education and training.

Comparing narcotics detection canine accuracy across breeds

Investigations of detection canine performance across breeds has yielded mixed results, often reporting behavioral differences observed by researchers or reported by handlers through surveys. The present study tested 34 narcotics detection canines; 25 Belgian Malinois and 9 German Shepherds to determine if there were any differences between the breeds in overall rate of detection accuracy and the number of false alerts in searches. As previously determined, results of the present study support the continued use of narcotic detection canines for law enforcement agencies (i.e., positive alert percentage >90%; false alert percentage <10%). The results indicate that Belgian Malinois and German Shepherds are statistically undifferentiated in their overall rate of narcotics detection accuracy [V(34) = 0.048, p = 0.778] and [χ2(1,34) = 0.080, p = 0.778]. The results further indicate that Belgian Malinois and German Shepherds are statistically undifferentiated in their number of false alerts in narcotics searches [V(34) = 0.133, p = 0.437] and [χ 2(1,34) = 0.604, p = 0.43].

The Shepherd and the Hunter: A Genomic Comparison of Italian Dog Breeds

Shepherd and hunting dogs have undergone divergent selection for specific tasks, resulting in distinct phenotypic and behavioural differences. Italy is home to numerous recognized and unrecognized breeds of both types, providing an opportunity to compare them genomically. In this study, we analysed SNP data obtained from the CanineHD BeadChip, encompassing 116 hunting dogs (representing 6 breeds) and 158 shepherd dogs (representing 9 breeds). We explored the population structure, genomic background, and phylogenetic relationships among the breeds. To compare the two groups, we employed three complementary methods for selection signature detection: FST, XP-EHH, and ROH. Our results reveal a clear differentiation between shepherd and hunting dogs as well as between gun dogs vs. hounds and guardian vs. herding shepherd dogs. The genomic regions distinguishing these groups harbour several genes associated with domestication and behavioural traits, including gregariousness (WBSRC17) and aggressiveness (CDH12 and HTT). Additionally, genes related to morphology, such as size and coat colour (ASIP and TYRP1) and texture (RSPO2), were identified. This comparative genomic analysis sheds light on the genetic underpinnings of the phenotypic and behavioural variations observed in Italian hunting and shepherd dogs.

What Is Written on a Dog's Face? Evaluating the Impact of Facial Phenotypes on Communication between Humans and Canines

Facial phenotypes are significant in communication with conspecifics among social primates. Less is understood about the impact of such markers in heterospecific encounters. Through behavioral and physical phenotype analyses of domesticated dogs living in human households, this study aims to evaluate the potential impact of superficial facial markings on dogs' production of human-directed facial expressions. That is, this study explores how facial markings, such as eyebrows, patches, and widow's peaks, are related to expressivity toward humans. We used the Dog Facial Action Coding System (DogFACS) as an objective measure of expressivity, and we developed an original schematic for a standardized coding of facial patterns and coloration on a sample of more than 100 male and female dogs (N = 103), aged from 6 months to 12 years, representing eight breed groups. The present study found a statistically significant, though weak, correlation between expression rate and facial complexity, with dogs with plainer faces tending to be more expressive (r = -0.326, p ≤ 0.001). Interestingly, for adult dogs, human companions characterized dogs' rates of facial expressivity with more accuracy for dogs with plainer faces. Especially relevant to interspecies communication and cooperation, within-subject analyses revealed that dogs' muscle movements were distributed more evenly across their facial regions in a highly social test condition compared to conditions in which they received ambiguous cues from their owners. On the whole, this study provides an original evaluation of how facial features may impact communication in human-dog interactions.

The Science and Social Validity of Companion Animal Welfare: Functionally Defined Parameters in a Multidisciplinary Field

Social validity refers to the social significance and acceptability of intervention goals, procedures, and outcomes. Animal practitioners, who are often guided by the principles of ABA, lack the benefit of verbal participants (at least with respect to target animals) with which to assess a client's needs and preferences. The study of a learner's welfare is useful for determining areas where intervention is needed or how the learner feels about an intervention that is underway. Three tenets of animal welfare measurement include physiological function, naturalistic behavior, and affect, where affect refers to private events, including emotions, which are a function of the same variables and contingencies responsible for controlling public behavior. The development of new technologies allows us to look "under the skin" and account for subjective experiences that can now be observed objectively. We introduce the reader to tools available from the animal welfare sciences for the objective measurement of social validity from the learner's perspective.

Function predicts how people treat their dogs in a global sample

Dogs have an extraordinary relationship with humans. We understand, communicate, and cooperate remarkably with our dogs. But almost all we know about dog-human bonds, dog behaviour, and dog cognition is limited to Western, Educated, Industrialized, Rich, Democratic (WEIRD) societies. WEIRD dogs are kept for a variety of functions, and these can influence their relationship with their owner, as well as their behaviour and performance in problem-solving tasks. But are such associations representative worldwide? Here we address this by collecting data on the function and perception of dogs in 124 globally distributed societies using the eHRAF cross-cultural database. We hypothesize that keeping dogs for multiple purposes and/or employing dogs for highly cooperative or high investment functions (e.g., herding, guarding of herds, hunting) will lead to closer dog-human bonds: increased primary caregiving (or positive care), decreased negative treatment, and attributing personhood to dogs. Our results show that indeed, the number of functions associates positively with close dog-human interactions. Further, we find increased odds of positive care in societies that use herding dogs (an effect not replicated for hunting), and increased odds of dog personhood in cultures that keep dogs for hunting. Unexpectedly, we see a substantial decrease of dog negative treatment in societies that use watchdogs. Overall, our study shows the mechanistic link between function and the characteristics of dog-human bonds in a global sample. These results are a first step towards challenging the notion that all dogs are the same, and open questions about how function and associated cultural correlates could fuel departures from the 'typical' behaviour and social-cognitive skills we commonly associate with our canine friends.

Understanding and preference toward DOs and OMT before and after an osteopathic principles and practice fellow lecture series

CONTEXT

One of the two major pathways to become a physician in the United States is the Doctor of Osteopathic Medicine (DO) degree. A major distinctive feature is often perceived as the addition of manual training in osteopathic manipulative treatment (OMT) in the DO education. However, the profession also has a distinct philosophy imbedded in the curriculum of all osteopathic medical schools. Many medical schools offer professional degrees with graduates who may choose to continue their education in medicine, such as the Master of Science in Biomedical Sciences (MSBS). At our institution, there is no formal exposure to the differences between osteopathic and allopathic medicine in the MSBS curriculum, and most of this understanding is gained through out-of-classroom conversations. During the SARS-CoV-2 pandemic, virtual learning prohibited the usual gathering and discourse that occurs when students are learning on campus.

OBJECTIVES

The objective of this study is to create a curriculum in the form of a seminar series to assist premedical students in making an informed choice about which profession is the best fit for their own education and to gain an appreciation for osteopathic medicine. This appreciation could also aid in the future collaboration of premedical students with osteopathic providers, recommendations to patients, and potentially their own medical care. Questionnaires were utilized to determine if our osteopathic seminar series was effective at changing the preferences and understanding of MSBS students. We also sought to determine the effectiveness of virtual vs. in-person delivery of our curriculum.

METHODS

A seminar series with pre-established objectives was developed and presented to MSBS students at an osteopathic institution during the Fall of 2020 and 2021. The 2020 seminar was delivered through a virtual conference platform, and the 2021 seminar was delivered in-person. An eight question pre-and postquestionnaire was given to participants to evaluate their preferences and understanding. Internal validity and differences between delivery formats were assessed.

RESULTS

Both seminar series produced equally effective, significant changes in the preferences and perceptions of osteopathic medicine in both virtual and in-person delivery formats. Differences in pre-vs. post understanding across both seminar series were not consistently significant and were smaller than those observed in preferences and perceptions. Positive changes included an increased willingness to see a DO and to recommend a loved one see a DO as their personal physician. Preference changes between the in-person vs. virtual delivery platforms did not show significant differences; however, understanding did show some inconsistent differences.

CONCLUSIONS

This study demonstrates the utility of a virtual or in-person seminar to improve the preferences and perceptions of the osteopathic profession in MSBS students. The seminar series was successful in its goal of offering formal exposure to the osteopathic profession. The improved preferences and perceptions will have potential substantial benefits to the field of osteopathic medicine in the future. Further research is warranted to determine the most effective way to increase understanding of the osteopathic profession.

Behavioural synchronization and social referencing of dogs and humans: walking in dyad vs in group

Recent studies have demonstrated that dogs synchronize their locomotor behaviour with that of their owners. The present study aims to improve our understanding of the sensorimotor processes underlying interspecific behavioural synchronization by testing the influence of the number of humans on dogs' behavioural synchronization. We used Global Positioning System (GPS) devices in an outdoor environment to measure dogs' behavioural synchronization to humans during a locomotor activity involving three speeds (static, slow walking and fast walking). For half of the dogs, only their owner was walking, while for the other half, the owner walked with two familiar people. We also tested the effect of dog breeds by involving 30 shepherd dogs and 30 molossoids. Our results showed that dogs exhibited the same level of behavioural synchronization with their owner if alone or if surrounded by two familiar people. Though the presence of a group of humans did not strengthen the dogs' locomotor synchronization, it did produce another effect: dogs gazed at their owners more frequently in the presence of a group compared to their owner alone. This result suggests the same level of locomotor social entrainment but a difference in social referencing depending on the number of humans.

Breed differences in social cognition, inhibitory control, and spatial problem-solving ability in the domestic dog (Canis familiaris)

The extraordinary genetic and behavioural diversity of dog breeds provides a unique opportunity for investigating the heritability of cognitive traits, such as problem-solving ability, social cognition, inhibitory control, and memory. Previous studies have mainly investigated cognitive differences between breed groups, and information on individual dog breeds is scarce. As a result, findings are often contradictory and inconsistent. The aim of this study was to provide more clarity on between-breed differences of cognitive traits in dogs. We examined the performance of 13 dog breeds (N = 1002 dogs) in a standardized test battery. Significant breed differences were found for understanding of human communicative gestures, following a human's misleading gesture, spatial problem-solving ability in a V-detour task, inhibitory control in a cylinder test, and persistence and human-directed behaviour during an unsolvable task. Breeds also differed significantly in their behaviour towards an unfamiliar person, activity level, and exploration of a novel environment. No significant differences were identified in tasks measuring memory or logical reasoning. Breed differences thus emerged mainly in tasks measuring social cognition, problem-solving, and inhibitory control. Our results suggest that these traits may have come under diversifying artificial selection in different breeds. These results provide a deeper understanding on breed-specific traits in dogs.

Effects of a Novel Gel Formulation of Dog Appeasing Pheromone (DAP) on Behavioral and Physiological Stress Responses in Dogs Undergoing Clinical Examination

Simple Summary

Safeguarding the health of dogs presupposes undergoing regular veterinary visits (VVs). However, the VV can be emotionally challenging, thus impairing the welfare of the patient, also reducing dog and owner compliance. The fear and anxiety experienced by the dogs evokes behavioral and physiological stress responses for adaptive purposes. It is therefore desirable to lower the stress from the visit. With this intent, we tested a gel formulation of a synthetic analogue of the appeasing pheromone secreted by bitches, the dog appeasing pheromone (DAP), as a situational support to improve the perception of the stay in the waiting room and the physical examination. In the waiting room, the dogs exposed to DAP exhibited changes in their behavior, namely significant decrease in lip licking, increase in panting, and nearly significant reduction of low body postures. On the examination table, neither behavioral nor physiological differences were found. DAP did not alter markedly the stress behavior and physiology of dogs during a VV, maybe due to a stress level exceeding the potential efficacy of the product. However, the change of a few stress-associated behaviors suggests that DAP could contribute to improving the welfare of dogs staying in the waiting room before the physical examination.

Abstract

The veterinary visit is necessary for safeguarding the health of dogs, but it can be stressful and threaten both the welfare of the patient and the accuracy of the examination. This randomized, triple-blind, placebo-controlled, crossover study aims at evaluating how dog appeasing pheromone (DAP) in a novel gel formulation influences the behavioral and physiological stress responses of 28 dogs undergoing a standardized clinical examination, while staying in the waiting room (WR) and visited in the examination room (ER). Behavioral responses were studied through behavioral categories and subjective scales (WR and ER). Autonomic response considered heart rate (WR and ER), blood pressure (WR and ER), respiratory rate (ER), and rectal temperature (ER). Neuroendocrine response considered salivary cortisol (WR and ER). In the waiting room, the use of DAP was associated with a significant reduction of lip licking (p = 0.0189), an increase in panting (p = 0.0276), and a reduction close to significance (p = 0.0584) of low body postures. No significant differences were observed within the physiological responses. In the examination room, neither behavioral nor physiological differences were found.

Sleep Characteristics in Dogs; Effect on Caregiver-Reported Problem Behaviours

Simple Summary

Sleep duration and quality can be difficult to assess. Clinicians working in the field of veterinary behavioural medicine with dogs showing problem behaviours currently have little evidence-based literature to guide recommendations on assessment of sleep or treatment options if sleep is deemed poor. This study aims to broaden the level of knowledge regarding canine sleep durations and characteristics and begin research into the relationship between behavioural responses and the duration and quality of sleep. A questionnaire was used to capture information regarding canine sleep characteristics and caregiver perceptions of the severity of problem behaviours shown by this cohort. Responses regarding 1330 dogs were received and assessed. Dogs shown to sleep less than 6 h whilst their caregivers are in bed showed a greater caregiver-reported severity of problem behaviours. Dogs more easily disturbed from sleep at times their caregiver was out of bed, showed increased reported severity of problem behaviours. Whilst it is not possible to determine an optimal canine sleep duration, sufficient evidence is presented to argue that addressing problem behaviours by recommending increased activity may not be appropriate when it results in deprivation in relation to species-specific sleep requirements.

Abstract

Optimal sleep duration and quality is difficult to define. There are strong arguments for a relationship between sleep, in particular REM sleep, and emotional health and behaviour in a variety of species. This study aims to broaden the level of knowledge regarding canine sleep durations and characteristics and begin research into the relationship between behavioural responses and the duration and quality of sleep. A caregiver questionnaire was used to capture information regarding the duration and characteristics of canine sleep, how easily this cohort of dogs were disturbed from sleep, and caregiver perceptions of the severity of problem behaviours shown by this cohort (n = 1330). A quadratic relationship between canine sleep duration whilst a caregiver is in bed and severity of problem behaviour is shown, with less than 8 h sleep and more than 10 h sleep correlating with increased severity of problem behaviours in this cohort. Dogs which were more easily disturbed from sleep at times their caregiver was out of bed, showed increased reported severity of problem behaviours. Whilst it is not possible to determine an optimal canine sleep duration, sufficient evidence is presented to argue that problem behaviour should not be remedied by sleep deprivation.

Health of Pug dogs in the UK: disorder predispositions and protections

BACKGROUND

Pugs are a brachycephalic dog breed that has become phenomenally popular over recent decades. However, there is growing concern about serious health and welfare issues in the breed. To augment the evidence-base on the comparative health of Pugs, this study aimed to compare the odds of common disorders between Pugs and all remaining dogs under primary veterinary care in the UK during 2016. A cross-sectional study design of VetCompass clinical records was used to estimate the one-year (2016) period prevalence for the disorders most commonly diagnosed in Pugs and non-Pugs. Risk factor analysis applied multivariable logistic regression modelling methods to compare the odds of 40 common disorders between Pugs and non-Pugs.

RESULTS

From a study population of 905,544 dogs, the analysis included random samples of 4308 Pugs and 21,835 non-Pugs. Pugs were younger (2.36 years, range 0.07-16.24 vs 4.44 years, range 0.01-20.46, p <  0.001) and lighter (8.95 kg, range 5.00-13.60 vs. 14.07 kg, range 1.41-85.00, p <  0.001) than non-Pugs. Pugs had 1.86 (95% confidence interval [CI] 1.72 to 2.01) times the adjusted odds of diagnosis with ≥1 disorder than non-Pugs. Pugs had significantly increased adjusted odds for 23/40 (57.5%) common disorders. These included: brachycephalic obstructive airway syndrome (odds ratio [OR] 53.92; 95% CI 36.22 to 80.28), stenotic nares (OR 51.25; 95% CI 24.93 to 105.37) and corneal ulceration (OR 13.01; 95% CI 10.50 to 16.11). Conversely, Pugs had significantly reduced adjusted odds of 7/40 (17.5%) common disorders compared to non-Pugs. These included: heart murmur (OR 0.23; 95% 0.13 to 0.14), lipoma (OR 0.24; 95% CI 0.11 to 0.55) and aggression (OR 0.31; 95% CI 0.21 to 0.47).

CONCLUSIONS

The current study highlights that predispositions outnumber protections between Pugs and non-Pugs for common disorders, suggesting some critical health welfare challenges to overcome for Pugs. Highly differing heath profiles between Pugs and other dogs in the UK suggest that the Pug has diverged substantially from mainstream dog breeds and can no longer be considered as a typical dog from a health perspective.

Ancestry-inclusive dog genomics challenges popular breed stereotypes

Behavioral genetics in dogs has focused on modern breeds, which are isolated subgroups with distinctive physical and, purportedly, behavioral characteristics. We interrogated breed stereotypes by surveying owners of 18,385 purebred and mixed-breed dogs and genotyping 2155 dogs. Most behavioral traits are heritable [heritability (h²) > 25%], and admixture patterns in mixed-breed dogs reveal breed propensities. Breed explains just 9% of behavioral variation in individuals. Genome-wide association analyses identify 11 loci that are significantly associated with behavior, and characteristic breed behaviors exhibit genetic complexity. Behavioral loci are not unusually differentiated in breeds, but breed propensities align, albeit weakly, with ancestral function. We propose that behaviors perceived as characteristic of modern breeds derive from thousands of years of polygenic adaptation that predates breed formation, with modern breeds distinguished primarily by aesthetic traits.

The Importance of Evaluating Positive Welfare Characteristics and Temperament in Working Therapy Dogs

To date, investigations of the welfare of therapy dogs have focused largely on examining physiological and behavioral measures that could indicate if the animal is experiencing stress or distress. However, this approach does not fully address the definition of welfare which is often described as existing on a continuum from negative (or stressful) to positive. With therapy dogs, it would be worth addressing if they experience positive emotional affect while working since the quality and efficacy of animal-assisted interventions for the human recipient is likely to be influenced by the animal's emotional state during the interaction. The purpose of this review is to articulate how objective measurements of the HPA axis and measurements of behavioral observations and standardized questions can be used to evaluate positive welfare in therapy dogs. A potentially relevant indicator of positive welfare is the peripheral concentration of the neurohormone oxytocin, which has been found to increase in systemic circulation within a variety of species during positive social and affiliative contexts, including during human-dog interaction. Oxytocin is also a negative-feedback regulator of the Hypothalamic-Pituitary-Adrenal (HPA) axis, which culminates with the production of the stress hormone cortisol. Cortisol is widely used as a physiological indicator to assess negative welfare states in animals, including therapy dogs. Observable behavior during interactions with humans that may convey enjoyment could provide indicators of positive welfare in dogs such as engagement in play, or human-directed affiliative behaviors including leaning against, nudging, or licking the patient. However, in assessing positive welfare, it is also critical to consider that all animal behavioral displays and physiological responses are dependent on the dog's individual (and breed) temperament. Temperament directly drives how the animal copes and responds to its current physical and social environment, including during stressful situations such as when therapy dogs interact with unfamiliar humans in novel healthcare settings. Coupled with both positive and negative physiological and behavioral welfare indicators, questionnaire data can provide further context to, and enhance interpretations of, therapy dog welfare assessment results. Overall, to date, no studies have measured all of these factors to assess therapy dog welfare.

Assessing the potential for infections of Echinococcus multilocularis in dogs in a hotspot of human alveolar echinococcosis infections in North America

Echinococcus multilocularis is a zoonotic tapeworm, whose metacestode larval stage is the etiological agent for alveolar echinococcosis in humans and is a parasite of emerging concern according to the World Health Organization which is difficult to diagnose and has a case mortality rate of >90% when left untreated. Echinococcus multilocularis requires two mammalian hosts to complete its lifecycle: wild and domestic canids as definitive hosts, and small mammals (mostly rodents) as intermediate ones. Because of their close relations with humans, domestic dogs have been indicated as a mean of infection to people. Human alveolar echinococcosis has historically been rare in North America, however, since 2013, at least seventeen diagnoses have been confirmed in Alberta, Canada. Because of this unprecedented series of cases, assessing the frequency of infections in dogs in Alberta is key to estimate risk for dog owners and animal health professionals. This study was carried out in Edmonton to determine the frequency of E. multilocularis infection in domestic dogs and potential risk factors. Fecal samples and corresponding behavior risk surveys were collected from 775 dogs in seven urban off-leash parks within Edmonton city limits during the summer of 2020. A quantitative PCR fecal test was used to diagnose E. multilocularis infection. We found a single case of E. multilocularis infection (1/775) and determined that the overall true prevalence was 0.2% (95% CrI: 0.0-0.7%) corrected for detection sensitivity and specificity. Overall, these findings confirm the presence of E. multilocularis infection in domestic dogs in Edmonton although further work is required to fully understand the risk factors that may contribute to infection and potential transmission to humans.

Challenges and Solutions Surrounding Environmental Enrichment for Dogs and Cats in a Scientific Environment

Simple Summary

Environmental enrichment is the provision of equipment or enhancement to an animal’s living area with the goal to improve animal welfare. Equipment is often provided without assessment of suitability or continuous revision. Enrichment constraints can vary between different animal settings and include limited space, budget and lack of opportunity for enhancement. Simple improvements and attention to the animal’s individual needs and preferences can allow further enrichment optimisation.

Abstract

Dogs and cats housed in research-, kennel- and cattery-type settings are reliant on caregivers to optimise their day-to-day experiences and welfare. The goal is to provide enriching environments for physical, social and environmental control; behavioural choice and opportunities to live as varied a life as possible. However, there are numerous challenges in these environments such as lack of appropriate enrichment for group housing, budget for equipment/training, study controls, time and space to make improvements. In addition, research settings are required to comply with legislation for care, husbandry and housing, and as standards differ between regions, conditions will vary between settings. Sharing knowledge in this field can only help drive a wider culture of care by helping improve the lives and welfare of animals cared for. This article presents some of the environmental enrichment strategies effective at the Waltham Petcare Science Institute, UK.

Is this love? Sex differences in dog-owner attachment behavior suggest similarities with adult human bonds

Sex differences in the behavioral responses of Labrador Retriever dogs in the Strange Situation Test were explored. Behaviors expressed by dogs during seven 3-min episodes were analyzed through a Principal Component Analysis (PCA). The scores of factors obtained were analyzed with a Generalized Linear Mixed Model to reveal the effects of the dog's sex and age and the owner's sex. In Episode 1 (dog and owner) and 5 (dog alone), the PCA identified three and two factors, respectively, which overall explained 68.7% and 59.8% of the variance, with no effect of sex. In Episodes 2 (dog, owner, and stranger), 3 and 6 (dog and stranger), and 4 and 7 (dog and owner), the PCA identified four factors, which overall explained 51.0% of the variance. Effects of sex were found on: Factor 1 (distress), with lower scores obtained by females in Episode 2 and higher in Episode 3; Factor 2 (sociability), which was overall higher in females; Factor 3 (separation-distress), with females, but not males, obtaining higher scores when left with the stranger than when with the owner. Therefore, females were overall more social but seemed more affected than males by the owner's absence. Parallels can be traced between our results and sex differences found in adult human romantic attachment, suggesting that the dog-owner bond has characteristics that are not found in the infant-mother relationship.

Genome-Wide Association Studies Reveal Neurological Genes for Dog Herding, Predation, Temperament, and Trainability Traits

Genome-wide association study (GWAS) using dog breed standard values as phenotypic measurements is an efficient way to identify genes associated with morphological and behavioral traits. As a result of strong human purposeful selections, several specialized behavioral traits such as herding and hunting have been formed in different modern dog breeds. However, genetic analyses on this topic are rather limited due to the accurate phenotyping difficulty for these complex behavioral traits. Here, 268 dog whole-genome sequences from 130 modern breeds were used to investigate candidate genes underlying dog herding, predation, temperament, and trainability by GWAS. Behavioral phenotypes were obtained from the American Kennel Club based on dog breed standard descriptions or groups (conventional categorization of dog historical roles). The GWAS results of herding behavior (without body size as a covariate) revealed 44 significantly associated sites within five chromosomes. Significantly associated sites on CFA7, 9, 10, and 20 were located either in or near neuropathological or neuronal genes including THOC1, ASIC2, MSRB3, LLPH, RFX8, and CHL1. MSRB3 and CHL1 genes were reported to be associated with dog fear. Since herding is a restricted hunting behavior by removing killing instinct, 36 hounds and 55 herding dogs were used to analyze predation behavior. Three neuronal-related genes (JAK2, MEIS1, and LRRTM4) were revealed as candidates for predation behavior. The significantly associated variant of temperament GWAS was located within ACSS3 gene. The highest associated variant in trainability GWAS is located on CFA22, with no variants detected above the Bonferroni threshold. Since dog behaviors are correlated with body size, we next incorporate body mass as covariates into GWAS; and significant signals around THOC1, MSRB3, LLPH, RFX8, CHL1, LRRTM4, and ACSS3 genes were still detected for dog herding, predation, and temperament behaviors. In humans, these candidate genes are either involved in nervous system development or associated with mental disorders. In conclusion, our results imply that these neuronal or psychiatric genes might be involved in biological processes underlying dog herding, predation, and temperament behavioral traits.

Characterizing unsuccessful animal adoptions: age and breed predict the likelihood of return, reasons for return and post-return outcomes

A considerable number of adopted animals are returned to animal shelters post-adoption which can be stressful for both the animal and the owner. In this retrospective analysis of 23,932 animal records from a US shelter, we identified animal characteristics associated with the likelihood of return, key return reasons, and outcomes post-return for dogs and cats. Binary logistic regression models were used to describe the likelihood of return, return reason and outcome based on intake age, intake type, sex, breed and return frequency. Behavioral issues and incompatibility with existing pets were the most common return reasons. Age and breed group (dogs only) predicted the likelihood of return, return reason and post-adoption return outcome. Adult dogs had the greatest odds of post-adoption return (OR 3.40, 95% CI 2.88-4.01) and post-return euthanasia (OR 3.94, 95% CI 2.04-7.59). Toy and terrier breeds were 65% and 35% less likely to be returned compared with herding breeds. Pit bull-type breeds were more likely to be returned multiple times (X2 = 18.11, p = 0.01) and euthanized post-return (OR 2.60, 95% CI 1.47-4.61). Our findings highlight the importance of animal behavior in the retention of newly adopted animals and provide useful direction for allocation of resources and future adoption counselling and post-adoption support services.

Come for the looks, stay for the personality? A mixed methods investigation of reacquisition and owner recommendation of Bulldogs, French Bulldogs and Pugs

Brachycephalic breeds are proliferating internationally, with dramatic rises in popularity juxtaposed with common and severe breed-related health problems. Physical appearance is as a dominant factor attracting owners to brachycephalic breeds; however, whether these owners will choose their current breed for future ownership and develop ‘breed-loyalty’ in the face of health problems is not yet known. The aims of this study were (1) to quantify levels of, and explore factors associated with, brachycephalic dog owners’ intentions to: (i) reacquire and/or (ii) recommend their current breed to potential first-time dog owners, and (2) to use qualitative methods to explore why brachycephalic dog owners would or would not recommend their current breed. This large mixed methods study reports on 2168 owners of brachycephalic breeds (Pugs: n = 789; French Bulldog: n = 741; Bulldogs: n = 638). Owners were highly likely to want to own their breed again in the future (93.0%) and recommend their breed to other owners (65.5%). Statistical modelling identified that first-time ownership and increased strength of the dog-owner relationship increased the likelihood of reacquisition and/or recommendation. In contrast, an increased number of health problems, positive perception of their dog’s health compared with the rest of their breed, and dog behaviour being worse than expected decreased the likelihood of reacquisition and/or recommendation. Thematic analyses constructed three themes describing why owners recommend their breed: positive behavioural attributes for a companion dog, breed suited to a sedentary lifestyle with limited space, and suitability for households with children. Five themes described why owners recommended against their breed: high prevalence of health problems, expense of ownership, ethical and welfare issues associated with breeding brachycephalic dogs, negative effects upon owner lifestyle and negative behavioural attributes. Understanding how breed-loyalty develops, and whether it can be attenuated, will be key to controlling the current population boom in brachycephalic breeds in the long-term.

Unravelling selection signatures in a single dog breed suggests recent selection for morphological and behavioral traits

Strong selection has resulted in substantial morphological and behavioral diversity across modern dog breeds, which makes dogs interesting model animals to study the underlying genetic architecture of these traits. However, results from between-breed analyses may confound selection signatures for behavior and morphological features that were coselected during breed development. In this study, we assess population genetic differences in a unique resource of dogs of the same breed but with systematic behavioral selection in only one population. We exploit these different breeding backgrounds to identify signatures of recent selection. Selection signatures within populations were found on chromosomes 4 and 19, with the strongest signals in behavior-related genes. Regions showing strong signals of divergent selection were located on chromosomes 1, 24, and 32, and include candidate genes for both physical features and behavior. Some of the selection signatures appear to be driven by loci associated with coat color (Chr 24; ASIP) and length (Chr 32; FGF5), while others showed evidence of association with behavior. Our findings suggest that signatures of selection within dog breeds have been driven by selection for morphology and behavior. Furthermore, we demonstrate that combining selection scans with association analyses is effective for dissecting the traits under selection.

No evidence for a relationship between breed cooperativeness and inequity aversion in dogs

Inequity aversion, the resistance to inequitable outcomes, has been demonstrated in a wide variety of animal species. Inequity aversion was hypothesised to have co-evolved with cooperation but only limited evidence supports this. Dogs provide a suitable model species to test this hypothesis as dogs were previously shown to be inequity averse and dog breeds vary in the extent to which they were selected for cooperativeness. Here, we compared the response of 12 individuals of "cooperative worker" breeds with that of 12 individuals of "independent worker" breeds in the "paw task" previously used to demonstrate inequity aversion in dogs. We also compared the two breed groups' subsequent social behaviours in a food tolerance test and free interaction session. Although subjects in both breed groups were inequity averse, we found no considerable difference between the groups in the extent of the negative response to inequity or in the impact of the inequity on subsequent social behaviours. However, we found differences between the breed groups in the response to reward omission with cooperative breeds tending to work for longer than independent breeds. Additionally, in the free interaction session, individuals of cooperative breeds spent more time in proximity to their partner in the baseline condition than individuals of independent breeds. Overall, our results do not provide support for the hypothesis that inequity aversion and cooperation co-evolved. However, they illuminate potential differences in selection pressures experienced by cooperative worker and independent worker dog breeds throughout their evolutionary history.

Estimating the heritability of cognitive traits across dog breeds reveals highly heritable inhibitory control and communication factors

Trait heritability is necessary for evolution by both natural and artificial selection, yet we know little about the heritability of cognitive traits. Domestic dogs are a valuable study system for questions regarding the evolution of phenotypic diversity due to their extraordinary intraspecific variation. While previous studies have investigated morphological and behavioral variation across dog breeds, few studies have systematically assessed breed differences in cognition. We integrated data from Dognition.com-a citizen science project on dog cognition-with breed-averaged genetic data from published sources to estimate the among-breed heritability of cognitive traits using mixed models. The resulting dataset included 11 cognitive measures for 1508 adult dogs across 36 breeds. A factor analysis yielded four factors interpreted as reflecting inhibitory control, communication, memory, and physical reasoning. Narrow-sense among-breed heritability estimates-reflecting the proportion of cognitive variance attributable to additive genetic variation-revealed that scores on the inhibitory control and communication factors were highly heritable (inhibitory control: h² = 0.70; communication: h² = 0.39), while memory and physical reasoning were less heritable (memory: h² = 0.17; physical reasoning: h² = 0.21). Although the heritability of inhibitory control is partially explained by body weight, controlling for breed-average weight still yields a high heritability estimate (h² = 0.50), while other factors are minimally affected. Our results indicate that cognitive phenotypes in dogs covary with breed relatedness and suggest that cognitive traits have strong potential to undergo selection. The highest heritabilities were observed for inhibitory control and communication, both of which are hypothesized to have been altered by domestication.

Morphometric Characteristics of the Skull in Horses and Donkeys-A Pilot Study

Horses and donkeys belong to the genus Equus, but important differences exist between the species, many of which affect their management and welfare. This study compared skull morphology between horses and donkeys. Horse (n = 14) and donkey (n = 16) heads were obtained post-mortem, sectioned sagittally close to the midline, and photographed for subsequent measurement of various skull structures. Skull, cranial, nasal, and profile indices were calculated for topographical comparisons between the species. The olfactory bulb area (OBA), OB pitch (the angle between the hard palate and the OB axis), and whorl location (WL) were also measured. A General Linear Model determined the main effect of species with Sidak's multiple comparisons of species' differences among the various measurements. There was no species difference in cranial or nasal indices (p > 0.13), but donkeys had a larger cranial profile than horses (p < 0.04). Donkeys had a smaller OBA (p < 0.05) and a steeper OB pitch (p < 0.02) than horses. The WL corresponded to the level of the OB in horses but was extremely rostral in donkeys (p < 0.0001). These results show clear differentiation in skull morphology between horses and donkeys. This may be useful in validating other physiological and behavioural differences between horses and donkeys.

Morphology does not covary with predicted behavioral correlations of the domestication syndrome in dogs

Domesticated animals display suites of altered morphological, behavioral, and physiological traits compared to their wild ancestors, a phenomenon known as the domestication syndrome (DS). Because these alterations are observed to co-occur across a wide range of present day domesticates, the traits within the DS are assumed to covary within species and a single developmental mechanism has been hypothesized to cause the observed co-occurrence. However, due to the lack of formal testing it is currently not well-resolved if the traits within DS actually covary. Here, we test the hypothesis that the presence of the classic morphological domestication traits white pigmentation, floppy ears, and curly tails predict the strength of behavioral correlations in support of the DS in 78 dog breeds. Contrary to the expectations of covariation among DS traits, we found that morphological traits did not covary among themselves, nor did they predict the strength of behavioral correlations among dog breeds. Further, the number of morphological traits in a breed did not predict the strength of behavioral correlations. Our results thus contrast with the hypothesis that the DS arises due to a shared underlying mechanism, but more importantly, questions if the morphological traits embedded in the DS are actual domestication traits or postdomestication improvement traits. For dogs, it seems highly likely that strong selection for breed specific morphological traits only happened recently and in relation to breed formation. Present day dogs therefore have limited bearing of the initial selection pressures applied during domestication and we should reevaluate our expectations of the DS accordingly.

A One Health Perspective on the Human-Companion Animal Relationship with Emphasis on Zoonotic Aspects

Over time the human-animal bond has been changed. For instance, the role of pets has changed from work animals (protecting houses, catching mice) to animals with a social function, giving companionship. Pets can be important for the physical and mental health of their owners but may also transmit zoonotic infections. The One Health initiative is a worldwide strategy for expanding collaborations in all aspects of health care for humans, animals, and the environment. However, in One Health communications the role of particularly dogs and cats is often underestimated.

OBJECTIVE

Evaluation of positive and negative One Health issues of the human-companion animal relationship with a focus on zoonotic aspects of cats and dogs in industrialized countries.

METHOD

Literature review.

RESULTS

Pets undoubtedly have a positive effect on human health, while owners are increasing aware of pet's health and welfare. The changing attitude of humans with regard to pets and their environment can also lead to negative effects such as changes in feeding practices, extreme breeding, and behavioral problems, and anthropozoonoses. For the human, there may be a higher risk of the transmission of zoonotic infections due to trends such as sleeping with pets, allowing pets to lick the face or wounds, bite accidents, keeping exotic animals, the importation of rescue dogs, and soil contact.

CONCLUSIONS

One Health issues need frequently re-evaluated as the close human-animal relationship with pet animals can totally differ compared to decennia ago. Because of the changed human-companion animal bond, recommendations regarding responsible pet-ownership, including normal hygienic practices, responsible breeding, feeding, housing, and mental and physical challenges conforming the biology of the animal are required. Education can be performed by vets and physicians as part of the One Health concept.

Food quantity discrimination in puppies (Canis lupus familiaris)

There is considerable evidence that animals are able to discriminate between quantities. Despite the fact that quantitative skills have been extensively studied in adult individuals, research on their development in early life is restricted to a limited number of species. We, therefore, investigated whether 2-month-old puppies could spontaneously discriminate between different quantities of food items. We used a simultaneous two-choice task in which puppies were presented with three numerical combinations of pieces of food (1 vs. 8, 1 vs. 6 and 1 vs. 4), and they were allowed to select only one option. The subjects chose the larger of the two quantities in the 1 vs. 8 and the 1 vs. 6 combinations but not in the 1 vs. 4 combination. Furthermore, the last quantity the puppies looked at before making their choice and the time spent looking at the larger/smaller amounts of food were predictive of the choices they made. Since adult dogs are capable of discriminating between more difficult numerical contrasts when tested with similar tasks, our findings suggest that the capacity to discriminate between quantities is already present at an early age, but that it is limited to very easy discriminations.

Intrinsic Ball Retrieving in Wolf Puppies Suggests Standing Ancestral Variation for Human-Directed Play Behavior

Domestication dramatically alters phenotypes across animal species. Standing variation among ancestral populations often drives phenotypic change during domestication, but some changes are caused by novel mutations. In dogs (Canis familiaris) specifically, it has been suggested that the ability to interpret social-communicative behavior expressed by humans originated post-domestication and this behavior is thus not expected to occur in wolves (Canis lupus). Here we report the observation of three 8-week-old wolf puppies spontaneously responding to social-communicative behaviors from an unfamiliar person by retrieving a ball. This behavioral expression in wolves has significant implications for our understanding and expectations of the genetic foundations of dog behavior. Importantly, our observations indicate that behavioral responses to human social-communicative cues are not unique to dogs. This suggests that, although probably rare, standing variation in the expression of human-directed behavior in ancestral populations could have been an important target for early selective pressures exerted during dog domestication.

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Dogs, unlike wolves, are suggested to have the ability to interpret human cues

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Yet, untrained wolf puppies will spontaneously retrieve a ball based on human cues

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Standing variation for human-directed behavior in ancestral wolf populations

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Human-directed behavior important during early selection in dog domestication

Expression of Behavioural Traits in Goldendoodles and Labradoodles

Simple Summary

Crossbred dogs are gaining in popularity with the general public, but we do not fully understand how these crossbreds behave compared to their parent breeds in regard to inherited behaviour traits. Because of this, we investigated behaviours exhibited by crossbred dogs by focusing on the popular Goldendoodle and Labradoodle crossbreds by comparing them to their corresponding parent or constituent breeds: Standard or Miniature Poodle, and Golden Retriever or Labrador Retriever. The data for this study was provided by 5141 volunteer dog owners from across the world who filled out the Canine Behavioural Assessment and Research Questionnaire (C-BARQ) online survey. The survey results were used to analyse fourteen different representative behavioural trait scores. As expected from a first-generation crossbred (F1), the crossbreds in our study tend to fall between the two parent breeds with some exceptions. The Goldendoodle displayed more problematic behaviour when compared to its constituent breeds, whereas the Labradoodle only differs significantly from the Miniature Poodle in dog rivalry. These results can help advise future dog owners on behavioural trends for particular crossbreds.

Abstract

As crossbred dogs gain in popularity, how they express inherited behaviour traits in comparison to their purebred constituent breeds is of interest. We investigated behaviours exhibited by crossbred dogs by focusing on the popular Goldendoodle and Labradoodle crossbreds and comparing them to their corresponding constituent breeds: Standard and Miniature Poodle, Golden Retriever or Labrador Retriever. The data for this study was provided by 5141 volunteer dog owners who filled out the Canine Behavioural Assessment and Research Questionnaire (C-BARQ) online survey. The survey results were used to analyse breed differences in fourteen representative behavioural trait scores: trainability, stranger-directed aggression, owner-directed aggression, dog-directed aggression, dog rivalry, dog-directed fear, stranger-directed fear, non-social fear, touch sensitivity, separation-related problems, excitability, attachment/attention-seeking behaviours, energy and chasing. As expected from a first-generation crossbred (F1), the crossbreds in our study tend to fall between the two constituent parent breeds with some exceptions. Our results suggest that the F1 Labradoodle differed significantly from one of the pure constituent breeds only in dog rivalry, whereas the F1 Goldendoodle behaviour varied from one or more pure constituent breeds in dog rivalry, dog-directed aggression, dog-directed fear, and stranger-directed fear. These results can help advise future dog owners on behavioural trends for particular crossbreds.

Assessment of emotional predisposition in dogs using PANAS (Positive and Negative Activation Scale) and associated relationships in a sample of dogs from Brazil

The English version of the Positive and Negative Activation Scale (PANAS) is a useful tool for the assessment of dog temperament, helping to identify highly sensitive individuals that could be at risk of developing fears, phobias and anxiety problems, and potentially depressive states. This study evaluated the association between dogs' and owners' characteristics and dog temperament in Brazil. To accomplish this, we adapted and validated a Portuguese language version of PANAS for dogs. Data from 1744 owner-dog dyads were analysed and a two-factor structure similar to the original PANAS was revealed that met the requirements for validity and internal consistency. We found that dogs owned by women, neutered dogs and those who live in single-dog households show higher negative activation. Moreover, the older the owner, the less the negative activation for dogs that are bought. We also found that the older the dog, the less the positive activation, but this score is higher in dogs that sleep inside the house. Interestingly, mixed-breed dogs scored higher for both negative and positive emotional activation compared to purebreds. These findings alongside the particular profile of dogs in Brazil, including its large population of mixed-breed, emphasise the value of cross-cultural investigations in order to develop a full understanding of dog behaviour.

Genetic dissection of complex behaviour traits in German Shepherd dogs

A favourable genetic structure and diversity of behavioural features highlights the potential of dogs for studying the genetic architecture of behaviour traits. However, behaviours are complex traits, which have been shown to be influenced by numerous genetic and non-genetic factors, complicating their analysis. In this study, the genetic contribution to behaviour variation in German Shepherd dogs (GSDs) was analysed using genomic approaches. GSDs were phenotyped for behaviour traits using the established Canine Behavioural Assessment and Research Questionnaire (C-BARQ). Genome-wide association study (GWAS) and regional heritability mapping (RHM) approaches were employed to identify associations between behaviour traits and genetic variants, while accounting for relevant non-genetic factors. By combining these complementary methods we endeavoured to increase the power to detect loci with small effects. Several behavioural traits exhibited moderate heritabilities, with the highest identified for Human-directed playfulness, a trait characterised by positive interactions with humans. We identified several genomic regions associated with one or more of the analysed behaviour traits. Some candidate genes located in these regions were previously linked to behavioural disorders in humans, suggesting a new context for their influence on behaviour characteristics. Overall, the results support dogs as a valuable resource to dissect the genetic architecture of behaviour traits and also highlight the value of focusing on a single breed in order to control for background genetic effects and thus avoid limitations of between-breed analyses.

Dogs, but Not Wolves, Lose Their Sensitivity Toward Novelty With Age

Selection of behavioral traits holds a prominent role in the domestication of animals, and domesticated species are generally assumed to express reduced fear and reactivity toward novel stimuli compared to their ancestral species. However, very few studies have explicitly tested this proposed link between domestication and reduced fear responses. Of the limited number of studies experimentally addressing the alterations of fear during domestication, the majority has been done on canids. These studies on foxes, wolves, and dogs suggest that decreased expression of fear in domesticated animals is linked to a domestication-driven delay in the first onset of fearful behavior during early ontogeny. Thus, wolves are expected to express exaggerated fearfulness earlier during ontogeny compared to dogs. However, while adult dogs are less fearful toward novelty than adult wolves and wolf-dog hybrids, consensus is lacking on when differences in fear expression arise in wolves and dogs. Here we present the first extended examination of fear development in hand-raised dogs and European gray wolves, using repeated novel object tests from 6 to 26 weeks of age. Contrary to expectations, we found no evidence in support of an increase in fearfulness in wolves with age or a delayed onset of fear response in dogs compared to wolves. Instead, we found that dogs strongly reduced their fear response in the period between 6 and 26 weeks of age, resulting in a significant species difference in fear expression toward novelty from the age of 18 weeks. Critically, as wolves did not differ in their fear response toward novelty over time, the detected species difference was caused solely by a progressive reduced fear response in dogs. Our results thereby suggest that species differences in fear of novelty between wolves and dogs are not caused by a domestication-driven shift in the first onset of fear response. Instead, we suggest that a loss of sensitivity toward novelty with age in dogs causes the difference in fear expression toward novelty in wolves and dogs.

Artificial selection for male winners in the Siamese fighting fish Betta splendens correlates with high female aggression

In Southeast Asia, males of the Siamese fighting fish Betta splendens have been selected across centuries for paired-staged fights. During the selection process, matched for size males fight in a small tank until the contest is resolved. Breeders discard losing batches and reproduce winner batches with the aim of increasing fight performance. We assessed the results of this long-term selection process by comparing under standard laboratory conditions male and female aggressive behaviour of one strain selected for staged fights ("fighters") and one strain of wild-types. The aggressive response of adult fish was tested against their mirror image or a size-matched conspecific. Fighter males were more aggressive than wild-type males for all measured behaviours. Differences were not only quantitative but the pattern of fight display was also divergent. Fighter males had an overall higher swimming activity, performing frequent fast strikes in the direction of the intruder and displaying from a distance. Wild-type males were less active and exhibited aggressive displays mostly in close proximity to the stimuli. Females of the fighter strain, which are not used for fights, were also more aggressive than wild-type females. Aggressive behaviours were correlated across male and female fighter siblings, suggesting common genetic and physiological mechanisms to male and female aggression in this species. The study further shows that results were largely independent of the stimulus type, with the mirror test inducing similar and less variable responses than the live conspecific presentation. These results suggest that selection for male winners co-selected for high-frequency and metabolic demanding aggressive display in males and also enhanced female aggression, opening a wide range of testable hypothesis about the ultimate and proximate mechanisms of male and female aggression in B. splendens.

Investigating risk factors that predict a dog's fear during veterinary consultations

Attending the veterinary clinic is an integral part of the physical welfare of every companion dog. However, some dogs experience their veterinary visits negatively, which poses a risk of injury to the veterinary staff, their guardian (owner) and themselves. It may also influence the regularity of non-urgent veterinary appointments. To date there have been conflicting reports relating to the proportion of dogs that show fear during their veterinary visits. In this study, we explored the risk factors associated with fear during veterinary examination and in novel situations (including first time at the veterinary clinic) from 26,555 responses in the Canine Behavioral Assessment and Research Questionnaire database. According to their guardians, 41% of companion dogs displayed mild to moderate fearful behaviour when examined by a veterinarian, and 14% exhibited severe or extreme fear. A similar trend was observed with dogs responding fearfully when in unfamiliar situations, including the dog’s first time at the veterinary clinic. Chi-squared tests showed every bivariate relationship between fear and the environmental and demographic factors measured was significant (p < 0.05). The most important predictors of fear in a veterinary examination were, in order: the dog’s breed group (27.1%), their history of roles or activities (16.7%), where they were sourced (15.2%), their weight (12%), the age of other dogs in the household (9.5%) and dog owner experience (6.3%). However, combined these risk factors only explain a total of 7% of variance of fear observed during veterinary examination. This suggests that fear exhibited during veterinary visits is common in dogs, but that the environment or human-animal interactions are likely to contribute more to prevalence and severity of this problem than the demographic factors measured here. We conclude by highlighting opportunities for future research aimed at facilitating less stressful veterinary visits for dogs and their guardians.

Breed Group Effects on Complaints about Canine Welfare Made to the Royal Society for the Prevention of Cruelty to Animals (RSPCA) Queensland, Australia

Cruelty- and neglect-related canine welfare concerns are important welfare and social issues. Dog breed has been identified as a risk factor for bad welfare, and yet its role in different types of canine welfare concerns has not been fully investigated. We conducted a retrospective study of 107,597 dog welfare complaints received by RSPCA Queensland from July 2008 to June 2018. The breed of the dog involved in the incident was either recorded as stated by the complainant or by the inspector attending the case. Dog breed was divided into groups following the Australian National Kennel Club nomenclature. Dogs of a non-recognised breed were more likely to be reported in welfare complaints than recognised breed dogs. Recognised breed dogs had a greater risk of being reported with poisoning, lack of veterinary support, abuse and being left unattended in a hot vehicle; while non-recognised breed dogs had greater risk of being reported with insufficient shelter, exercise and food/water, as well as overcrowding and abandonment. Utility breeds, terriers and working dogs were most likely to be reported, while toy, non-sporting breeds and gundogs were least likely to be reported. Common complaint types for utility dogs were: insufficient food/water, shelter and exercise, and poor living conditions; for terriers: abandonment, intentional abuses and killing or injuring another animal; for working dogs: insufficient food/water, shelter and exercise; for toy dogs: lack of veterinary care, overcrowding and staying in a hot vehicle alone; for non-sporting dogs: lack of veterinary care, being left in a hot vehicle unattended and poor body conditions; and for hounds: killing or injuring another animal, intentional abuses and poor body conditions. Breed groups rather than breeds may be the best method of breed identification in a public reporting system as they group similar breeds together, and as our research shows, they relate to types of animal welfare complaints. Understanding the relationship between breed group and canine welfare complaints may help authorities improve public education programs and inform decision-making around which breed a new owner should choose.