Aggression In Dogs Research Articles

Choice of conflict resolution strategy is linked to sociability in dog puppies

Measures that are likely to increase sociability in dog puppies, such as appropriate socialisation, are considered important in preventing future fear or aggression related problems. However, the interplay between sociability and conflict behaviour has rarely been investigated. Moreover, while many studies have addressed aggression in domestic dogs, alternative, non-aggressive conflict resolution strategies have received less scientific attention. Here we tested 134 Border collie puppies, aged 40–50 days, in a personality test which included friendly interactions with an unfamiliar person, exposure to a novel object, and three brief restraint tests. Considering the latter to be mild ‘conflict’ situations, we analysed whether the puppies’ behaviour in the restraint tests was related to their sociability or to their boldness towards the novel object. Strategies employed by the puppies during restraint tests included trying to interact socially with the experimenter, remaining passive, and attempting to move away. In line with findings from humans and goats, puppies scoring high on sociability were more likely to adopt an interactive conflict resolution strategy, while those with low sociability scores tended to react passively. In contrast, avoidance behaviours were unrelated to sociability, possibly reflecting inconsistency in the flight strategy in dogs. Boldness towards a novel object was not related to sociability or to puppies’ reactions in restraint tests. This is one of the first studies to demonstrate a link between sociability and conflict resolution strategies in non-human animals.

A quick assessment tool for human‐directed aggression in pet dogs

Many test series have been developed to assess dog temperament and aggressive behavior, but most of them have been criticized for their relatively low predictive validity or being too long, stressful, and/or problematic to carry out. We aimed to develop a short and effective series of tests that corresponds with (a) the dog's bite history, and (b) owner evaluation of the dog's aggressive tendencies. Seventy-three pet dogs were divided into three groups by their biting history; non-biter, bit once, and multiple biter. All dogs were exposed to a short test series modeling five real-life situations: friendly greeting, take away bone, threatening approach, tug-of-war, and roll over. We found strong correlations between the in-test behavior and owner reports of dogs' aggressive tendencies towards strangers; however, the test results did not mirror the reported owner-directed aggressive tendencies. Three test situations (friendly greeting, take-away bone, threatening approach) proved to be effective in evoking specific behavioral differences according to dog biting history. Non-biters differed from biters, and there were also specific differences related to aggression and fear between the two biter groups. When a subsample of dogs was retested, the test revealed consistent results over time. We suggest that our test is adequate for a quick, general assessment of human-directed aggression in dogs, particularly to evaluate their tendency for aggressive behaviors towards strangers. Identifying important behavioral indicators of aggressive tendencies, this test can serve as a useful tool to study the genetic or neural correlates of human-directed aggression in dogs.

Food-related aggression in shelter dogs: A comparison of behavior identified by a behavior evaluation in the shelter and owner reports after adoption

In order to assess the relationship between food-related aggression in the shelter as identified by a standardized canine behavior evaluation and owner-reported food-related aggression after adoption, this retrospective cohort study followed 97 dogs adopted from a shelter and their adoptive owners. The Match-Up II Shelter Dog Rehoming Program, a standardized canine behavior evaluation that was administered to all the dogs in the study prior to adoption, was used to classify dogs as either food aggressive (FA+) or not food aggressive (FA−). Adoptive owners were subsequently surveyed to assess the dogs’ behavior after adoption, the owners’ perception of food-related aggression, and their satisfaction with the dog as a pet. Twenty (20.6%) dogs evaluated were deemed FA+ in the shelter, and slightly more than half (11/20; 55%) of them were later reported by adopters as exhibiting FA+ behavior in the home after adoption, whereas out of the 77 dogs that were deemed to be FA− in the shelter, 17 (22%) were reported to be FA+ by adopters; conversely, the majority (60/77; 78%) of dogs identified as FA− in the shelter were reported by adopters as not having exhibited FA+ behavior in the home (P=0.004). Most adopters, including those whose dogs were reported FA+ in the home, did not consider FA+ behavior to be a challenge to keeping the dog as a pet. In conclusion, in this sample of shelter dogs, the observation of FA+ behavior during a standardized dog behavior evaluation was associated with FA+ behavior in the home following adoption, however, an almost equal number of dogs observed to be FA+ on the behavior evaluation did not show food aggression after adoption. Failure to observe FA+ behavior on the shelter test was associated with the absence of FA+ behavior after adoption. The detection of FA+ via a behavior evaluation should be interpreted with caution, since a positive finding in the shelter evaluation does not consistently indicate that the behavior will occur in the home nor that a dog is unsuitable for adoption.

Caracterização de casos de agressão canina em Campinas, São Paulo, Brasil

A retrospective study was conducted with information on the cases of canine aggression notified in 2009 in the municipality of Campinas, state of São Paulo, Brazil. Information was obtained from 87 (3.8%) out of 2,281 cases. Cumulative incidence of canine aggression was 2.42% per year (CI95%: 2.32-2.51) per 1000 inhabitants. Most victims of aggressive dogs were men (53.0%), adults (72.0%), and owners (52.9%). The attacks occurred mainly in the street (55.2%), while the victim was interacting with the dog (79.3%), and the upper limbs were the most affected part of the body (49.4%). Most of these dogs were males (74.7%), adults (74.3%), mixed-breed (65.5%), not castrated (98.9%), restricted (55.2%), without training (98.1%), and half of them had already bitten. Canine aggression was not associated to sex, breed, reproductive status, type of restrain, and training, because frequency distribution of these variables among the canine population of Campinas is unknown. In order to develop preventive protocols for dog bites, populational studies assessing the characteristics and prevalence of dog aggression are needed.

Prairie Dog Aboveground Aggressive Behavior Towards Black-footed Ferrets

Black-footed ferrets typically prey upon prairie dogs at night while prairie dogs are presumably sleeping. Prairie dogs can act aggressively towards aboveground ferrets in daylight and we observed prairie dog aggression towards ferrets four times in South Dakota and Montana. Ten behaviors by prairie dogs were recorded during aggressive interactions with ferrets including chasing, blocking, and physical contact. One of the aggressive prairie dogs was confirmed as an adult male and three of four encounters occurred Jun. through Jul. Interactions lasted <10 min and neither the prairie dog nor ferret were visibly injured.

The effect of thyroid replacement in dogs with suboptimal thyroid function on owner-directed aggression: A randomized, double-blind, placebo-controlled clinical trial

Abstract The efficacy of thyroid hormone replacement therapy (THRT) as treatment for owner-directed aggression in client-owned dogs with low thyroid hormone levels was evaluated by means of a 6-week-long, parallel design, double-blind placebo-controlled study. The designation of borderline hypothyroid was made if the dog's free normal thyroxine (T4) value was frankly low or in the bottom 20th percentile of the normal range and either total T4, total triiodothyronine (T3), or free T3 was frankly low or in the bottom 30th percentile of the normal range. The presence of thyroid autoantibodies also qualified a dog for enrollment. Owners recorded the number of aggressive episodes directed toward family members on a daily basis for 8 weeks (2-week baseline phase and 6-week study phase). Twenty-nine dogs completed the study; 14 in a treatment group and 15 in a placebo group. The median number of aggressive episodes per day decreased significantly from baseline in both treated and placebo group dogs in weeks 1-2, 3-4, 5-6, and week 6 (treatment, χ 2 = 24.8, P 2 = 20.2, P 2 = 4.047, P = 0.044). Three thyroxine-treated dogs had borderline-low thyroid levels on the final day of the study (day 42). When aggression frequency was compared between the treatment and placebo groups after the removal of 3 thyroxine-treated dogs, the treatment group did not have a significantly lower aggression frequency than the placebo group during week 6 (Kruskal–Wallis statistic: χ 2 = 3.035, n=26, P = 0.08). The authors discuss the role of thyroid hormones in the regulation of aggression and other cognitive issues and provide rationale for using THRT in dogs exhibiting owner-directed aggression that also have low normal or baseline thyroid hormone levels.

Inter-dog aggression in a UK owner survey: prevalence, co-occurrence in different contexts and risk factors

Aggression between dogs is common and can result in injury. The aims of this study were to estimate prevalence, evaluate co-occurrence with human-directed aggression, and investigate potential risk factors, using...

Investigating behavior assessment instruments to predict aggression in dogs

This masked controlled study evaluated a group of dogs to determine if the results of two behavior assessments detected aggression in dogs that had a history of aggression according to a validated questionnaire for measuring behavior and temperament traits in dogs. Groups of dogs with or without a history of aggression were identified from owner-completed questionnaires for 67 dogs. Any dogs that had a maximum score of no greater than 1 for any question comprising aggression factors were placed in the low/no aggression group and any dogs that had a maximum score of 2 or higher on any question comprising the aggression factors were placed in the moderate to severe aggression group. This second group was further divided to separate moderate aggression from severe aggression. Two behavior assessments, Meet Your Match (MYM)™ Safety Assessment for Evaluating Rehoming™ (SAFER™) (SAFER) and a modified version of Assess-A-Pet (mAAP), were administered to each dog in random order by assistants masked to the dogs’ behavioral histories. The scores for each assessment were divided into binary categorizations (no aggression or aggression). For SAFER, the aggression category was further divided, separating dogs that showed fear, arousal or inhibited aggression from those that showed moderate aggression, and from those that showed severe aggression. The previously established categories for the mAAP of ‘no issue’, ‘unsocial’, ‘borderline’ and ‘fail’ were also used. Subtest scores for each assessment were also summed. With binary categorization, SAFER showed both lower sensitivity and specificity at 0.60 (95% confidence limits (CL)=0.44, 0.74) and 0.50 (95% CL=0.28, 0.72) respectively, than mAAP at 0.73 (95% CL=0.58, 0.85) and 0.59 (95% CL=0.36, 0.79) respectively. The odds ratio showed that an aggressive dog was 4.1-fold more likely to be classified in an aggression group by the mAAP test and 1.5 times more likely by SAFER. When the assessments were split into multiple categories, SAFER results were no longer significant, but mAAP maintained a statistically significant but weak correlation of 0.34 (P=0.005) with historical aggression categories. SAFER testing was unable to identify dogs with moderate aggression that could potentially be addressed with behavior modification. By independently selecting acceptable levels of false positive or false negative results for the assessment, summed score results could be used in shelters as an aid to selecting dogs for adoption. Behavioral assessment results should be used in conjunction with other information such as intake history and staff observations to make an informed outcome decision for an individual dog.

Validity of model devices used to assess canine temperament in behavioral tests

Temperament tests are widely accepted as instruments for profiling behavioral variability in dogs, and they are applied in numerous areas of investigation (e.g. suitability for adoption or for breeding). During testing, to elicit a dog's reaction toward novel stimuli and predict its behavior in everyday life, model devices such as a child-like doll, or a fake dog, are often employed. However, the reliability of these devices to accurately stimulate dogs’ reactions to children or dogs, is unknown and perhaps overestimated. This may be a particular concern in the case of aggressive behavior toward humans, a significant public health issue. The aim of this study was to: (1) evaluate the correlation between dogs’ reactions to these devices, and owners’ reports of their dog's aggression history (using the C-BARQ©); (2) compare reactions toward the devices of dogs with and without histories of aggression. Subjects were selected among those visiting for behavioral consultation at the Veterinary Hospital of the University of Pennsylvania, and previously categorized as aggressive toward unfamiliar children, conspecifics, or as non-aggressive dogs (control). The test consisted of different components: an unfamiliar female tester approaching the dog; the presentation of a child-like doll, an ambiguous object, and a fake plastic dog. All tests were videotaped and durations of behaviors were later analyzed on the basis of a specified ethogram. Dogs’ reactions were compared to C-BARQ scores, and interesting correlations emerged for ‘dog-directed aggression/fear’ (R=0.48, P=0.004), and ‘stranger-directed aggression’ (R=0.58, P<0.001) factors. Dogs differed in their reactions toward the devices: the child-like doll and the fake dog elicited more social behaviors than the ambiguous object used as a control stimulus. Issues concerning the reliability of these tools to assess canine temperament are discussed.

Pain-related aggression in dogs: 12 clinical cases

Abstract The aim of this retrospective study was to describe the main features of pain-related aggression in dogs. Twelve dogs presented for aggressive problems at the Veterinary Hospital of the Autonomous University of Barcelona, Spain, were included, and a questionnaire was used to gather information on the context of the aggression, body posture during the attack, impulsiveness, and aggressive behavior before the onset of the pain-eliciting condition. The most common cause of pain was hip dysplasia (66.7%), but no relationship was found between the cause of pain and the characteristics of the aggressive behavior. Dogs were classified as having been aggressive before or after the onset of painful condition. Dogs that had not been aggressive before the onset of the pain-eliciting condition were more impulsive ( df = 1, χ 2 = 5.3, P = 0.0209), showed aggression as a result of manipulation context more frequently ( df = 1, χ 2 = 6, P = 0.0143), and adopted a defensive body posture more frequently ( df = 1, χ 2 = 3.733, P = 0.0533) than dogs that had been aggressive before the onset of pain. These results suggest that previous expression of aggressive behavior has a major effect on the pattern of pain-related aggression in dogs.

Spontaneous Mammary Carcinomas in Female Dogs: Association between Immunohistochemical Degrees of Neoplasia Aggressiveness and Residual Pyrethroids

Of the tumors diagnosed in the female dogs have the highest mammary neoplasias incidence. These neoplasias can be influenced by environmental contaminants. Despite evidence of pyrethroid toxicity, carcinogenic potential has not yet been sufficiently elucidated, there is a need to investigate their involvement in mammary tumor. In previous studies, pyrethroid residues were detected in female dogs with mammary neoplasia, however was not investigate the influence of this insecticide in the genesis and aggressiveness of mammary cancer. This study aimed to investigate possible relations between pyrethroid residues and aggressiveness of mammary carcinoma in female dogs. Fifty selected female dogs were divided into five groups of 10 animals each: the Control group, female dogs without mammary neoplasia; the groups Luminal A, Luminal B, HER-2 Superexpression and Basal were constituted by female dogs that presented inguinal mammary carcinoma classified immunohistochemically. The aggressiveness of carcinomas was evaluated by immunohistochemistry (HER-2, p63, estrogen receptor). Residual concentrations of the pyrethroids from the mammary gland and fat tissue adjacent to it were determined by HPLC. Data were analyzed by Chi-Square test. Of the all animals, six presented residues of pyrethroids in mammary samples and 10 presented it in fat tissue samples. There was no statistical evidence that pyrethroids are involved in mammary carcinoma aggressiveness in female dogs.

Situated Activities in a Dog Park: Identity and Conflict in Human-Animal Space

Abstract This study examines how people engage with the dynamic environment of the dog park in the face of unclear or ambiguous rules and emergent norms. Using participant observation, the analysis shows how, in the formal dog park, caretakers become “control managers” who must negotiate problems related to a variety of dog behaviors, especially mounting, aggression, and waste management. In this process, caretakers use various strategies to manage their own and others’ possible perceptions and understandings of appropriate behavior for dogs in public places.

Etología clínica y agresividad canina en Montevideo: implicancia de las razas y el sexo

Statistics about clinical data is lacking in Uruguay. Herein, we present an account of canine behavioral problems recorded from different sources: a) clinical reports on canine behaviour, from 30 veterinary clinics in Montevideo city from 2005 to 2007 (n = 179); b) records of dog attacks to people (n = 992) reported at the Servicio de Atención al Mordido (Ministerio de Salud Pública, same period); and c) conflicts from records of Comisión Nacional Honoraria de Zoonosis (n = 44,000). Based on these data we discus common behavioral problems, types of aggression involved, the frequency of male / female, if they were neutered or not and the age at the onset of the first episodes of aggression. For each record we obtained an aggressive risk factor associated to breed. The results are consistent with international reports, where the aggression was the most common behavioral problem (58.9%), and dominance aggression has the highest proportion (56%). The RDPCC records revealed that the proportion of animals involved in aggression is similar in both genders. However, SAM-MSP records showed that males (71%) were a significantly greater proportion than females (29%). Our data from RDPCC showed that 100% of males involved in aggression towards people were whole, while 38.5% females were castrated. The first signs of canine aggression towards people were observed in first year of life in 56.5% of cases. On the other hand, while the RDPCC record suggests that Cocker breed tended to show more attacks of aggression toward people, the SAMMSP record pointed to the German Shepher as the more aggressive breed. The Rottweiler and Uruguayan Cimarron, occupied the first and third place respectively in the aggressive risk factor rank associated to breed, both in RDPCC and SAM-MSP set of records. This is the first descriptive work on dog behavior problems and aggression in Montevideo, where also is shows the implication of the Cimarron uruguayo race in aggression.

Dog aggression: canine behavior and factors contributing to aggression toward humans

DOG AGGRESSION: CANINE BEHAVIOR AND FACTORS CONTRIBUTING TO AGGRESSION TOWARD HUMANS J. Kottferov a*, T. Jakuba, D. Fed akov a, J. Marekov a, M. Fejs akov a, J. Ki sov a, O. Ondra sovi cov a, M. Ondra sovi c University of Veterinary Medicine and Pharmacy in Ko sice, Komensk eho 73, 041 81 Ko sice, Slovakia Institute of Social Sciences Slovak Academy of Sciences, Ko sice, Slovakia *Corresponding author: kottfer@uvm.sk; Phone: 1421 915 984 670

Testing for human directed aggression in dogs

s 59 incorrectly to 2% of commands and 40% of commands elicited no response from the dogs. There was considerable variation across participants’ timing of reinforcement with the latency to deliver the first instance of reinforcement (secondary or primary) ranging from 0 to. 5 seconds. No significant difference was found between owners’ latency to deliver secondary or primary reinforcement (t (5) 5 21.66, P 5 0.16) or between the times taken to reinforce ‘sit’ or ‘down’ responses (t (5) 5 20.65, P 5 0.54) (first instance of reinforcement). Results showed a positive correlation between the time to the first instance of reinforcement and the proportion of incorrect responses (r (7)5 0.65, P5 0.12). We conclude that given the wide range of latencies to reinforcement, it is possible that the dogs’ task acquisition was suboptimal at times. Delays to reinforcement may also give room for unintentional feedback to occur, particularly as dogs are so receptive to human-given cues. Ongoing research will attempt to address these questions.

Excessive mouthing in puppies as a predictor of aggressiveness in adult dogs

s 93 covering 2.991 km and home to about 1.4 million people in 2010. Contact was first made by email; phone calls were made to those who had not responded after 2 months. Forty-eight (74%) of the cities and villages and 22 of the police districts (76%) submitted copies of their regulations. Dogs’ access to at least one public spacedsuch as sport centres, public buildings, play grounds, beaches, and public parksdis forbidden in 14% of the cities/villages and 26% of the police districts. Some of these cities/villages also forbid certain breeds of dogs; pit bulls or pit bull mixes are always included in regulations that forbid certain breeds. Twenty four percent of the cities/villages and 37% of the police districts specify public areas (viz., public spaces, some parks, cemeteries, and forests) where dogs have access only when on a leash. Thirteen (27%) of the cities/villages and 14 (64%) of the police districts sanction loud barking. In 31% of the cities/ villages and in 50% of the police districts, owners are required to control their dogs in public places. In only 3 (14%) of the police regulations owners are forbidden from involving dogs in dogfights. Only 21% of all cities/villages and 23% of all police districts back infractions with either prison terms or fines (V1–25). In general, the regulations vary between adjacent municipal region and even with the overlaying police district(s), making it difficult to know which regulations to follow. Little coordination was found in enforcing or understanding conflicting regulations. Given the difficulty associated with knowing and enforcing these conflicting dog safety ordinances, we recommend a concerted effort to draft national regulations informed by objective, scientifically-based knowledge.

Evaluation of behaviour testing for human directed aggression in dogs

Behaviour test batteries are used to identify aggressive dogs. The Dutch Socially Acceptable Behaviour (SAB)-test has been used since 2001 to select against unwanted aggression and fear in specific dog breeds, though much is unknown yet regarding its reliability, validity and feasibility. In this paper the SAB-test is evaluated and the results describe its usefulness for identifying aggression towards humans in dogs. Behaviour test outcomes on 345 dogs (479 records on tests performed indoor and outdoor) scored by the judges of the Dutch Kennel Club were compared to owner reported assessments of their dogs’ behaviour prior to testing. Dogs were labelled aggressive when having bitten a human at least once according to the owner and were diagnosed by the judges as such when attacking at least once during the SAB-test. Aggressive dogs showed significantly more attacks than non-aggressive controls and a Principal Components Analysis of detailed observations on 76 dogs grouped aggressive behaviours like growl, bare teeth, snap, lunge and bite in one dimension, confirming the test's validity. Analysis of 479 test records revealed a sensitivity, specificity and accuracy of 0.33, 0.81 and 0.64, respectively. The specificity could be increased to 0.93 by raising the threshold for positive test results to at least 2 attacks during the test. The low sensitivity is explained by the decision to classify dogs as aggressive on the basis of one bite incident only and by a relative weak capacity of the test to detect specific forms of aggression. The reliability of the test was investigated by comparing test outcomes on 133 dogs when tested indoor and outdoor. The accuracy decreased from 0.67 to 0.62, but overall the indoor test outcomes were similar to those found outdoors. Scores for aggression and anxiety were significantly higher when dogs were tested for the first time in the morning than the second time in the afternoon, suggesting desensitization. Salivary cortisol concentrations in 20 dogs were not different in samples taken before and after the test, which oppose severe levels of stress. The SAB-test allows one to evaluate aggression in dogs, but present findings indicate that probably those that behave aggressively in the absence of fear remain undetected. It is recommended to increase the test's usefulness by refining or including new test components that target different forms of aggression. Formulating a risk assessment based on detailed information on a dog's behaviour during testing instead of simply producing a pass–fail judgement will facilitate a purpose specific use of the SAB-test.

Factores de manejo que influyen en la presentación de conductas agresivas en perros

Dog aggression is the behaviour problem that presents more risks for humans and other animals, because of the potential damage that this behaviour can cause. The accidents to aggressive behaviours in dogs, affect millions of people every year. The problem of the aggressiveness in dogs is complex, because this conduct is determined by several different factors. It is described that around 30% of behaviour in dogs, is determined by genetic or intrinsic factors, while the 70% remainder is determined by the environmental factors and conditions that surround the dog.The purpose of the present study is to offer information of different variables that influence the presentation of aggressive behaviours in dogs, so it can be used to generate technical criteria that support an adequate legislation about the control and management of potentially aggressive dogs.The purpose of the present studuy is to offer information of different variables that influence the presentation of aggressive behaviours in dogs, so it can be used to generate technical criteria that support an adequate legislation about the control and management of potentially aggressive dogs.For these purpose opinion polls where applied to: breeders, dog trainers and owners. Eleven breeds were selected: Rottweiler, Pitbull, Akita Inu, Dogo Argentine, Bull Mastiff, Mastin Napolitano, Doberman, Saint Bernard, Great Danish, German Shepard and mixed race dogs.The results show that, for the dogs involved in the study, there is a statistically significant relation between the presentation of aggressive behaviours and the variables breed, sex, relation of the pet with the family group, type of advising received, information of the breed characteristics, place in which the pet was acquired, age of the pet at moment of acquirement, methods utilized to establish the dominance, training and purpose of training. For the breeders of dogs was established that, the parent's selection is mainly based on physical features and pedigree, and in a second place in temperament gestures. In all the breeding places an interview is made to ascertain the living conditions and characteristics of the pet, but if the results are not satisfactory for the breed, only half of the breeders do not sell the dog. Half of the trainers uses physical submission to dominate the dog, and nine of ten polled trainers carry out some training that enhance the protection behaviour and aggressiveness in dogs, these kind of training is most often requested for Rottweiler, Akita Inu, German Shepard.

Association of dopamine‐ and serotonin‐related genes with canine aggression

Human-directed canine aggression was studied using 50 aggressive and 81 non-aggressive dogs. We examined 62 single nucleotide polymorphisms (SNPs) occurring in or in the close vicinity of 16 neurotransmitter-related genes. Allelic associations with aggression were identified for DRD1, HTR1D, HTR2C and SLC6A1. Risk or protective haplotypes for aggressive behaviour based on 2-5 SNPs were identified. The frequency of aggressive dogs varied significantly between the haplotypes within loci and the odds ratios of aggression in dogs with risk haplotypes compared with protective haplotypes varied from 4.4 (HTR2C) to 9.0 (SLC6A1). A risk haplotype across the neurotransmitter receptor gene HTR1D harboured a non-synonymous SNP with a potential effect on protein function. We identified no haplotypes in complete association with the recorded phenotypes, supporting a complex inheritance of aggression.

Factors associated with aggressive responses in pet dogs

This study used The Canine Behavioral Assessment and Research Questionnaire (C-BARQ) and regression models to explore the relative importance of dog and owner characteristics, living environment and owner–dog interaction to household dogs’ aggressiveness towards strangers, owners and other dogs. Exploratory factor analysis revealed 10 interpretable factors from the Chinese translation of C-BARQ: stranger-directed aggression, owner-directed aggression, dog-directed aggression, social fear, nonsocial fear, separation-related behavior, attachment or attention-seeking behavior, trainability, excitability and pain sensitivity. The factor structure of our study largely resembled that reported in Hsu and Serpell (2003) and van den Berg et al. (2006; Dutch translation of C-BARQ) . All factors of the translated C-BARQ have adequate reliability (Cronbach α : 0.74–0.93) and are thus suitable for measuring temperament traits in Taiwan's pet dogs. Intrinsic and environmental variables important to the three aggression subscales were not entirely the same, but breed ( P ≤ 0.020) and physical punishment ( P ≤ 0.053) had significant relationships with all of them. Golden Retriever scored the lowest while dogs subjected to physical reprimands scored significantly higher on aggression subscales. In addition, higher scores on stranger-directed aggression were associated ( P ≤ 0.027) with living in rural areas, in houses with yard space and with more household members and being acquired either as puppies or for guarding purposes. Higher scores on owner-directed aggression were associated ( P ≤ 0.040) with male and older dogs, being neutered/spayed, having female owners, fewer other dogs in the household and being kept outside the house. Higher scores on dog-directed aggression, on the other hand, were associated ( P ≤ 0.050) with living in houses with either yard space or more household members and with spending less time with owners. Stranger- and dog-directed aggression had more important intrinsic and environmental variables common to them than did owner-directed aggression, which suggests that aggression towards owners may be regulated by different mechanisms from aggression towards strangers and other dogs. Although no causal relationship between dog aggression and environmental variables can be implied from observational studies, the results of this and other studies lend support to the possibility of reducing dogs’ aggressive responses through proper management by owners.