FULL PAPER Ethology

A Comparison of the Behavioral Profiles of Purebred in Japan to Profiles of those in the United States and the United Kingdom

Yukari TAKEUCHI1) and Yuji MORI1)

1)Laboratory of Veterinary Ethology, The University of Tokyo, 1–1–1 Yayoi, Bunkyo-ku, Tokyo 113–8657 Japan

(Received 8 December 2005/Accepted 28 March 2006)

ABSTRACT. To clarify the behavioral profiles of 56 pure breeds of dogs in Japan, 96 small-animal veterinarians participated in a question- naire survey using the same criteria as in preceding studies conducted in the United States and the United Kingdom. We found significant differences among breeds in all behavioral traits examined. In addition, gender differences were revealed in terms of aggression to dogs, territorial defense, excitability, general activity, dominance over owner, destructiveness, watchdog barking, and snapping at children, which were all rated higher in males than females, whereas obedience training and housebreaking ease were rated higher in females. No gender differences were evident in playfulness, excessive barking, or affection demand. Using factor analyses, “aggressiveness”, “reac- tivity”, and “trainability” were determined to be consistent with results found in the US and UK surveys. On the basis of these factor scores, seven groups of breeds were determined by cluster analysis to compare to the US survey; 22 of the 38 breeds common with the US survey were categorized into the same groups as those in that survey. The results demonstrated differences in canine behavioral pre- disposition among breeds and between genders. The similarity in the results between our study and previous surveys, which involved distinct geographical locales, suggests that the genetic basis of breed-specific temperamental traits is manifested irrespective of the cul- tural or regional identities of the owners. KEY WORDS: behavioral trait, breed difference, canine, gender difference, questionnaire survey. J. Vet. Med. Sci. 68(8): 789–796, 2006

The is one of the most heavily domesticated animals compared to European and North American owners, and has been subjected to intensive artificial selection to because most dogs in Japan were traditionally held outside meet various utilitarian demands, such as hunting, guarding, as watchdogs until recently and are still used as watchdogs and herding. Some breeds are therefore genetically special- in rural areas. While experts such as behaviorists and train- ized to fulfill specific physical and/or instinctive roles. Con- ers have been emphasizing the importance of understanding sequently, the behavioral profiles of purebred dogs have the behavioral profile of a purebred dog before becoming a become highly diversified. Nearly half a century ago, a dog owner, many prospective owners tend to select dogs at large-scale investigation was conducted in an attempt to pet shops based on features such as body size and color. evaluate the heritability of specific behavioral traits in vari- Moreover, in Japan, sales booms of particular breeds have ous canine breeds by analyzing those behavioral traits in occurred in the past, and it is speculated that these booms dogs raised in the same environment over several genera- have resulted in various behavioral problems after the pas- tions in the Jackson Laboratory [18]. Other attempts to sage of a fad simply because of haphazard breeding pro- reveal breed differences in behavioral traits were performed grams and inadequate preweaning. It appears that these at the University of California, Davis [6–8]. A similar sur- sales booms are caused not only by a lack of knowledge of vey was carried out in the United Kingdom about 10 years the historical background of purebred dogs, but also by the later to compare the behavioral traits of purebred dogs there absence of information on the behavioral profiles of pure- to those in the United States [2, 3]. In the UC-Davis study, bred dogs in Japan, which has been said to be derived from the authors surveyed obedience judges and veterinarians relatively small numbers of ancestral individuals for each about their opinions on 13 behavioral characteristics of 56 breed and selective breeding in accordance with Japanese representative breeds and found significant breed differ- custom. ences in all traits [8]. Taking the history of domestication This study was conducted to gather information on the into account, these breed differences in behavioral traits are behavioral profiles of purebred dogs in Japan, which could derived in part from genetic factors, although environmental be important for future research on behavior genetics and and experiential factors are also involved. Based on this could also provide reliable information to prospective dog premise, we attempted to determine the genetic factors owners. By replicating the questionnaire survey conducted responsible for these behavioral traits [9, 11, 13–16, 19, 20]. in both the United States [7, 8] and the United Kingdom [3], The number of dogs in Japan has increased from 9 million we could directly compare our results to these earlier sur- in 1994 to 11 million in 2003, and more than half are esti- veys. mated to be purebred (Pet food manufactures association, Japan; http://www.jppfma.org/index.html, in Japanese). MATERIALS AND METHODS However, it is generally acknowledged that the Japanese know less about how to appropriately interact with dogs A questionnaire survey was taken by 96 veterinary prac- 790 Y. TAKEUCHI AND Y. MORI titioners in Japan according to the procedure described in ted), and also to indicate whether males or females were previous US and UK surveys [3, 7, 8]. Forty-eight veteri- more likely to exhibit that behavior. Basically, each breed narians were recruited from the mailing list of the “Japanese was evaluated for behavioral traits by 12 veterinarians. veterinary society for the study of animal behavior; http:// However, because they were allowed to skip the breed with www.vm.a.u-tokyo.ac.jp/koudou/vbhHP/, in Japanese”, and which they considered unfamiliar, the actual number of vet- 48 additional veterinarians were enlisted by core members erinarians who evaluated each breed varied between 5 and of this society. Of the 96 respondents, 58 (60%) were male. 12 depending on breeds and behavioral traits (10–12 veteri- The participants resided across the country but were mainly narians for 80% of breeds in this study). The methods for located in the Tokyo and Osaka areas. On average, they had data processing were in accordance with the previous 14.5 years of clinical experience (range: 1–50 years). All reports [3, 7, 8]. respondents were contacted via fax or e-mail to which a All statistics, including factor analysis using the principal questionnaire, a guide for the survey, and a detailed descrip- factor method with varimax rotation and a cluster analysis tion of each rated behavioral trait were attached. The 56 with the method of k-means, were conducted with Stat- breeds were selected for the survey based on the rankings of graphics Centurion XV (http://www.statgraphics.com/). their average numbers registered during the period 1999– Cluster analysis was performed based on the scores of fac- 2003. The information was obtained from the web site of tors 1, 2, and 3 obtained in this study, which corresponded to the Japan , Inc. (http://www.jkc.or.jp/jkc_info/ factors 2, 1, and 3, respectively, of the US survey. The Jap- index.html, in Japanese). The 56 breeds selected in this anese clusters were produced by incorporating one breed as study are presented in Table 5. a “seed” for each US cluster for comparison to the structure The questionnaire referred to 13 criteria as in the previous of clusters in the US survey. The seed breeds (shown in studies [3, 7, 8], i.e., excitability, general activity, snapping Table 5 with bold and italic font) were selected as the repre- at children, excessive barking, playfulness, obedience train- sentative breeds in Japan. ing, watchdog barking, aggression to dogs, dominance over owner, territorial defense, affection demand, destructive- RESULTS ness, and housebreaking ease. The respondents were asked to rank the seven breeds from the lowest to the highest level Breed differences in behavioral traits: Behavioral traits of expression for each behavior (same ranks were permit- ranked in order of decreasing reliability in differentiating

Table 1. Behavioral traits ranked in order of decreasing reliability in differentiating between dog breeds, as indicated by magnitude of the F-ratio, and the five highest and five lowest breeds for each behavioral trait in Japanese survey

Behavioral trait F-ratio P-value Highest (plane) and lowest (italic) 5 breeds of each behavioral trait (each averaged score was shown in parentheses)

Playfulness 6.97 <.0001 Labrador Retriever (6.5), Golden Retriever (6.3), Border Collie (6.2), Flat-Coated Retriever (5.9),Pembroke Welsh Corgi (5.8), Great Dane (1.8), Saint Bernard (1.7), Great Pyrenees (1.7), Borzoi (1.6), (1.5) Excessive barking 6.78 <.0001 Kaninchen Dachshund (6.4), Maltese (6.3), Pomeranian (6.2), Yorkshire Terrier (6.1), (6.0) Afghan (2.3), Saint Bernard (1.8), Newfoundland (1.8), Borzoi (1.5), Bulldog (1.3) Affection demand 6.17 <.0001 Miniature Dachshund (6.2), Labrador Retriever (6.2), Toy Poodle (6.1), Cavalier King Charles Spaniel (5.9), Maltese (5.7), German Shepherd Dog (2.0), Borzoi (1.9), Great Dane (1.8), Saint Bernard (1.8), Akita (1.6) General activity 5.81 <.0001 Border Collie (6.8), Jack Russell Terrier (5.8), Miniature Pinscher (5.8), Wire Fox Terrier (5.6), Shetland Sheepdog (5.5) Chin (1.9), Great Pyrenees (1.6), Saint Bernard (1.5), Bulldog (1.4), (1.3) Aggression to dogs 5.54 <.0001 Pembroke Welsh Corgi (6.5), Miniature Pinscher (6.4), (6.3), Cairn Terrier (5.9), Akita (5.9), Pekingese (2.3), Saint Bernard (2.3), Cavalier King Charles Spaniel (2.3), Italian (2.2), Flat-Coated Retriever (2.0) Watchdog barking 4.96 <.0001 Miniature Pinscher (6.3), Shiba Inu (6.2), Shetland Sheepdog (6.1), German Shepherd Dog (5.8), Doberman Pinscher (5.6), Saint Bernard (2.1), Great Dane (2.0), Newfoundland (1.9), Bulldog (1.8), Basset Hound (1.7) Territorial defense 4.76 <.0001 Miniature Pinscher (6.4), Shiba Inu (6.2), German Shepherd Dog (6.0), Doberman Pinscher (5.9), Pembroke Welsh Corgi (5.8), Labrador Retriever (2.2), Frise (2.0), (2.0), Golden Retriever (2.0), Chin (1.5) Snapping at children 4.49 <.0001 Miniature Pinscher (6.6), Chihuahua (6.4), Pembroke Welsh Corgi (6.3), Cairn Terrier (5.7), Shiba Inu (5.6) Flat-Coated Retriever (2.3), Labrador Retriever (2.2), Borzoi (2.2), Newfoundland (2.0), Saint Bernard (1.7) Excitability 4.44 <.0001 Beagle (5.8), Kaninchen Dachshund (5.8), Jack Russell Terrier (5.7), Miniature Pinscher (5.6), Chihuahua (5.4) Chin (2.1), Borzoi (2.0), Bulldog (1.7), Saint Bernard (1.6), Basset Hound (1.5) Obedience training 3.24 <.0001 Labrador Retriever (6.5), Doberman Pinscher (6.3), Golden Retriever (6.0), Flat-Coated Retriever (5.8), German Shepherd Dog (5.7), Pekingese (2.5), Miniature Pinscher (2.5), Chihuahua (2.4), Basset Hound (2.4), Miniature (1.9) Dominance over owner 2.99 <.0001 Afghan Hound (6.4), Pembroke Welsh Corgi (6.2), Wire Fox Terrier (5.8), Miniature Bull Terrier (5.8), Miniature Pinscher (5.8), Labrador Retriever (2.6), Golden Retriever (2.5), Flat-Coated Retriever (2.3), Bichon Frise (2.3), Sain Bernard (2.1) Destructiveness 2.94 <.0001 Pembroke Welsh Corgi (6.0), Beagle (5.8), Cairn Terrier (5.7), Kaninchen Dachshund (5.5), Jack Russell Terrier (5.5) Bulldog (2.3), Borzoi (2.2), Pekingese (2.1), Chin (2.0), Italian Greyhound (1.8) Housebreaking ease 1.43 0.0293 Golden Retriever (6.3), Flat-Coated Retriever (5.5), Borzoi (5.3), Great Dane (5.0), Standard Dachshund (5.0) West Highland White Terrier (3.0), Old English Sheepdog (3.0), Bernese Mountain Dog (2.9), Miniature Bull Terrier (2.8), Bulldog (2.3) BEHAVIORAL PROFILES OF PUREBRED DOGS IN JAPAN 791

Table 2. Overlapping breeds for each behavioral trait between Japanese and US surveys (from ref. 6 pp. 34-59.) comparing extreme 11 breeds Irish Setter, Shetland Sheepdog, Golden Retriever Pekingese, Akita, Saint Bernard, Basset Hound, Bulldog Beagle, Cairn Terrier, Yorkshire Terrier Old English Sheepdog, Great Dane, Newfoundland Toy Poodle, Shih Tzu, Maltese, Yorkshire Terrier , Saint Bernard, Great Dane, Basset Hound, Akita Irish Setter, Wire Fox Terrier Akita, Rottweiler, Saint Bernard, Newfoundland, Bulldog, Basset Hound Wire Fox Terrier Newfoundland, Golden Retriever Doberman Pinscher, German Shepherd Dog, Cairn Terrier, Yorkshire Terrier Bulldog, Basset Hound, Saint Bernard, Newfoundland German Shepherd Dog, Doberman Pinscher, Wire Fox Terrier Bichon Frise, Pug, Golden Retriever, Basset Hound Pomeranian,Yorkshire Terrier, Chihuahua, Wire Fox Terrier, Maltese Newfoundland, Labrador Retriever, Golden Retriever Wire Fox Terrier, Yorkshire Terrier, Chihuahua Great Dane, Akita, Saint Bernard, Rottweiler, Newfoundland, Basset Hound Doberman Pinscher, Shetland Sheepdog, German Shepherd Dog, Golden Retriever, Labrador Retriever Pekingese, Pomeranian, Chihuahua, Basset Hound, Afghan Hound, Wire Fox Terrier Afghan Hound, Wire Fox Terrier, Chihuahua Bichon Frise, Labrador Retriever, Golden Retriever Wire Fox Terrier, Irish Setter, West Highland White Terrier, Dalmatian Chihuahua, Akita, Pekingese, Bulldog Bichon Frise, Akita, Shetland Sheepdog Basset Hound The upper (plane font) of each behavioral category shows highest breeds and the lower (italic font) shows lowest breeds. The concordance rate between Japanese and USA surveys was shown after each behavioral category. between dog breeds, as indicated by the magnitude of the F- barking, excitability, general activity, snapping at children, ratio, are shown in Table 1. Significant breed differences territorial defense, and watchdog barking. In this regard, the were observed in all behavioral traits (ANOVA, p<0.0001, Saint Bernard (7 times), Flat-Coated Retriever (6), Labrador except for housebreaking ease: p<0.05, F(55, 457)=1.43 to Retriever (6), Golden Retriever (5), Bulldog (5), Borzoi (5), 6.97). The five highest and five lowest scoring breeds for and Chin (4) were the most frequently ranked breeds in each behavioral trait are also shown in Table 1. The Saint terms of favorable traits, and the Miniature Pinscher (8 Bernard (9 times), Miniature Pinscher (8), Borzoi (7), Pem- times), Pembroke Welsh Corgi (5), and Shiba Inu (4) were broke Welsh Corgi (7), Flat-Coated Retriever (6), Bulldog found to exhibit unfavorable traits most frequently. (6), and Labrador Retriever (6) appear most frequently at To identify the breeds that have common characteristics both extremes. between the Japanese and US surveys, the 11 highest-rank- When we categorized the 13 traits as either favorable or ing breeds, which corresponded to the breeds of decile ranks unfavorable on the basis of their facilitating the ease of rear- 10 and 9 in the US survey [6] and the 11 lowest-ranking ing by inexperienced owners, the favorable traits included breeds, which corresponded to the breeds of decile ranks 2 affection demand, housebreaking ease, obedience training, and 1 in the US survey, were compared in each behavioral and playfulness, whereas unfavorable traits were aggression trait between the two surveys. Overlapping breeds for each to dogs, destructiveness, dominance over owner, excessive behavioral trait are shown in Table 2. The averaged concor- 792 Y. TAKEUCHI AND Y. MORI

Table 3. Factor loading(s) of each behavioral characteristic in Japanese survey Behavioral characteristic Factor 1 Factor 2 Factor 3 Aggression to dogs 0.828 Snapping at children 0.743 Territorial defense 0.774 Dominance over owner 0.726 Watchdog barking 0.712 Playfulness 0.860 Affection demand 0.768 General activity 0.692 Excitability 0.511 0.668 Excessive barking 0.536 0.594 Destructiveness 0.531 Housebreaking ease 0.814 Obedience training 0.717

one of the three factors (the absolute value of factor loading was more than 0.4), as shown in Table 3. Factor 1, “aggres- siveness”, accounted for 37.7% of the variance and was associated with aggression to dogs, snapping at children, territorial defense, dominance over owner, and watchdog barking. Factor 2, “reactivity”, accounted for 17.1% and was associated with playfulness, affection demand, general activity, and destructiveness. Excitability and excessive barking were nearly equally weighted on both factors 1 and 2. Factor 3, “trainability”, was associated with housebreak- ing ease and obedience training. A comparison of the factor structures among the Japa- nese, US, and UK surveys revealed that similar factors Fig. 1. Gender analysis of 13 behavioral traits. The quantitative belonging to mostly common behavioral traits were rating was determined by “(the number of veterinarians rating extracted among these three surveys with a few exceptions males higher— those rating females higher)/total number of vet- erinarians × 100”. The black columns indicate that males were such as factor 4 (investigation) in the US survey and factor rated significantly higher, gray columns denote that females 3 (immaturity) in the UK survey, as shown in Table 4. were rated significantly higher, and white columns represent Cluster analysis: According to the cluster analysis using traits for which a significant number of veterinarians considered the k-means method on each of the three factors, seven clus- no gender difference. ters of breeds were generated, as shown in Table 5. Twenty- two of 38 breeds in common with the US survey were cate- dance rate was 49.3%, with a range between 26.7 (house- gorized into the same groups as those of that survey, and 14 breaking ease) and 68.8 (obedience training). of 35 breeds in common with the UK survey were catego- Gender differences in behavioral traits: The gender anal- rized into the same groups as those of that survey. yses of the 13 behavioral traits are shown in Fig. 1. Veteri- narians found no gender differences in some behavioral DISCUSSION traits such as playfulness, excessive barking, and affection demand (χ2 test for goodness of fit, p<0.0005, except for In this study, we observed significant breed differences in playfulness p<0.05, χ2 =4.17 to 35.04, df=1). Regarding the all behavioral traits examined, which were mostly in accor- other behavioral traits, significantly more veterinarians dance with those reported in preceding studies in the United rated males higher than females in aggression to dogs, terri- States [8] and the United Kingdom [3]. Between the US and torial defense, excitability, general activity, dominance over UK surveys, obedience training was the only inconsistency owner, destructiveness, snapping at children, and watchdog regarding breed differences, and the UK authors speculated barking (χ2 test for goodness of fit, p<0.0001, χ2 =28.45 to that the working potential of dogs was regarded as more 85.00, df=1), whereas females were ranked higher in obedi- important in the United States, whereas their role as com- ence training and housebreaking ease (χ2 test for goodness panions may have been more valued in the United Kingdom of fit, p<0.0001, χ2 =21.36, 27.94, respectively, df=1). for some guarding and watchdog breeds. This may be true Factor analysis: The factor analysis resulted in the for the situation in Japan as well, since many native Japa- extraction of three main factors with eigenvalues greater nese dogs such as the Shiba Inu and Akita have been kept as than 1.0. The three factors together accounted for 63.3% of watchdogs and guarding dogs. A similar survey conducted the common variance, and each item belonged to more than in Japan, which involved 54 veterinarians who evaluated 19 BEHAVIORAL PROFILES OF PUREBRED DOGS IN JAPAN 793

Table 4. Comparison of factor structure among Japanese, US (Table 1 from ref. 7) and UK surveys (Table 1 from ref. 3) Factor 1 Factor 2 Factor 3 (aggressiveness) (reactivity) (trainability) Aggression to dogs Playfulness Housebreaking ease Snapping at children Affection demand Obedience training Territorial defense General activity Dominance over owner Excitability^ Watchdog barking Excessive barking^ Destructiveness ^Excitability and Excessive barking were also loaded on factor 1 Factor 2 Factor 1 Factor 4 Factor 3 (aggressiveness) (reactivity) (investigation) (trainability) Territorial defence Affection demand Destructiveness Oberience training Watchdog barking Excitability Playfulness Housebreaking ease Aggression to dogs Excessive barking Dominance over owner Snapping at children General activity Factor 1 Factor 2 Factor 3 Factor 4 (aggressivity) (reactivity) (immaturity) (housetrainability) Territorial defence Snapping at children* Playfulness Ease of housetraining Dominance over owner Excessive barking Destructiveness Watchdog behavior Excitability General activity# Aggression to dogs Affection demand Snapping at children* *Snapping at children was equally weighted on both factors 1 and 2 #General activity was also loaded on factor 2 The common behavioral traits among three surveys belonging same factor were shown in bold. breeds including five native to Japan [21], identified no sig- inexperienced owners. The notable point is that the Pem- nificant breed differences in terms of playfulness or obedi- broke Welsh Corgi and Kaninchen Dachshund, both of ence training. The inconsistency with our results may be which have been extremely popular during sales booms in attributable to differences in the breeds selected and the Japan, were categorized as unfavorable breeds. This may sampling size. When we compared the F-ratios, which indi- have resulted from veterinarians having an unfavorable cate the reliability of distinguishing among breeds, to those impression of these breeds through repeated exposure to in the US survey [8], dramatic differences were found in various behavioral problems, which were probably attribut- general activity, snapping at children, excitability, obedi- able to haphazard breeding and/or inappropriate weaning ence training, dominance over owner, and affection programs attributable to the sudden increase in market demand. In our survey, the F-ratios for these traits, except demands. for affection demand, were smaller than those in the US sur- When the 11 extreme breeds for each behavioral trait vey, which suggests that Japanese veterinarians considered were compared between our survey and the US survey, the these traits to be less different among breeds than the author- concordance rate was on average 49.3% (range: 26.7 to ities in the United States did. 68.8). Unfortunately, the raw data used in the UK survey It is interesting to note the most frequently ranked breeds were no longer available, so we were unable to compare in Table 1, which indicate that veterinarians viewed these among the three world regions, i.e., North America, Europe, breeds as having extremely overlapping traits. The situation and Asia. Nevertheless, the breeds listed in Table 2 have is very similar to that in the US survey, although the fre- common characteristics in both Japan and the United States. quently occurring breeds are completely different. When In addition, breeds characteristic of specific behavioral traits we simply divided the 13 behavioral traits into two types, such as aggression to dogs and housebreaking ease may be i.e., favorable and unfavorable traits, the Saint Bernard, different between two countries and/or they may be ambig- three retrievers, the Bulldog, Borzoi, and Chin were in the uous because the concordance rate was relatively smaller most frequently ranked breeds for favorable traits, and the than for other traits. Miniature Pinscher, Pembroke Welsh Corgi, Kaninchen Regarding gender differences in the 13 behavioral traits, Dachshund, Shiba Inu, and German Shepherd were the most the overall trend that females were rated higher than males frequently ranked for unfavorable traits. These results indi- in obedience training, housebreaking ease, and affection cate that the breeds in the former group are more suitable for demand but lower in the other ten behavioral traits was con- 794 Y. TAKEUCHI AND Y. MORI

Table 5. Seeded cluster analysis of factor scores for Japanese breeds to US breeds high aggression, high reactivity, medium trainability Pomeranian (1, 1) American Cocker Spaniel (1, 1) Yorkshire Terrier (1, 1) Beagle (1, 2) Irish Setter (1, 2) Maltese (1, –) Pug (1, –) Miniature Schnauzer (7, 1) Miniature Dachshund (–, 1)Dalmatian (3, 5) Pembroke Welsh Corgi (4, 7) Scottish Terrier (7, 3) Cairn Terrier (7, 7) Wire Fox Terrier (7, 7) Cavalier King Charles Spaniel (–, 4) Papillon (–, 4) Jack Russell Terrier (–, 7) (–, –) Kaninchen Dachshund (–, –) Miniature Pinscher (–, –) Shiba Inu (–, –) low aggression, low reactivity, low trainability Basset Hound (2, 2) Bulldog (2, 3) Miniature Bull Terrier (–, –) low aggression, low reactivity, medium trainability (3, –) Afghan Hound (3, –) Saint Bernard (3, –) Old English Sheepdog (2, 3) Pekingese (1, 1) Rottweiler (6, 6) Bichon Frise (4, –) Newfoundland (5, –) Italian Greyhound (–, 2) Chin (–, –) Great Pyrenees (–, –) medium aggression, high reactivity, high trainability Shetland Sheepdog (4, 5) English Springer Spaniel (4, 4) Toy Poodle (4, 4) Standard Dachshund (7, 1) Border Collie (–, 5) very low aggression, very high reactivity, high trainability Labrador Retriever (5, 5) Golden Retriever (5, 5) Boston Terrier (1, –) Flat-Coated Retriever (–, –) high aggression, low reactivity, high trainability German Shepherd Dog (6, 6) Doberman Pinscher (6, 6) Akita (6, –) Great Dane (3, 3) Boxer (3, 5) Borzoi (–, –) medium aggression, medium reactivity, low trainability West Highland White Terrier (7, 7) Chihuahua (7, 1) Shih Tzu (4, 1) English Cocker Spaniel (–, 1) Bernese Mountain Dog (–, –) French Bulldog (–, –) Common breeds between Japanese and USA or UK surveys were shown in bold. Breeds used as cluster seeds were shown in bold and italic. USA cluster numbers (former) and UK cluster numbers (latter) were shown in parentheses. sistent with the US and UK surveys. However, differences neutered dogs in the latest survey by Hart and Hart [5]. existed in terms of the magnitudes of difference and the sig- The factor analysis revealed three main factors, “aggres- nificance levels. These results indicate that veterinarians’ siveness”, “reactivity”, and “trainability”. This factor struc- impressions of gender differences were common among the ture was consistent with those of the US and UK surveys three countries irrespective of cultural and/or regional dif- (Table 4) [3, 7]. However, destructiveness and playfulness ferences. This trend of gender differences appears to be were placed in “reactivity” in our study, whereas these traits derived not only from the activational effect of but also from were assigned in “investigation” and “immaturity” in the US the organizational effect of the sexual steroid hormone in and UK studies, respectively. These minor discrepancies addition to genetic factors, as the results were consistent may have been due to the methodological difference of fac- when veterinarians were asked about the behavioral traits of tor analysis or the differences in the selected breeds among BEHAVIORAL PROFILES OF PUREBRED DOGS IN JAPAN 795 the studies. their data. We also thank DVM Yukihide Momozawa and Using the seeded cluster analysis, all breeds surveyed in Mrs. Megumi Takeuchi for help with data processing. this study were categorized into seven clusters based on the US survey. 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Med. genetics research, including our own ongoing studies [9, 11, Sci. 67: 199–201. 13–16, 19, 20]. 10. Houpt, K. A. and Willis, M. B., 2001. Genetics of behaviour. The reasons and motivations for having dogs vary from pp. 371–400. In: The Genetics of the Dog (Ruvinsky, A. and owner to owner; some want a watchdog for security while Sampson, J. eds.), CABI Publishing, New York. 11. Ito, H., Nara, H., Inoue-Murayama, M., Shimada, M. K., others desire a companion for family members. If veterinar- Koshimura, A., Ueda, Y., Kitagawa, H., Takeuchi, Y., Mori, ians working at clinics know the behavioral profiles of pure- Y., Murayama, Y., Morita, M., Iwasaki, T., Ota, K., Tanabe, Y. bred dogs and the tendencies in gender differences shown in and Ito, S. 2004. Allele frequency distribution of the canine this study, they can more appropriately advise prospective dopamine receptor D4 gene exon III and I in 23 breeds. J. Vet. owners. This can facilitate a better quality of human-animal Med. Sci. 66: 815–820. bond and perhaps prevent behavioral problems due to a mis- 12. Machenzie, S. A., Oltenacu, E. A. B. and Houpt, K. A. 1986. match between dogs and owners. In addition, veterinarians Canine behavioral genetics - a review. Appl. Anim. Behav. Sci. should inform potential owners of the importance of under- 15: 365–393. standing the pedigree line within a breed, the behavior of the 13. Masuda, K., Hashizume, C., Kikusui, T., Takeuchi, Y. and dam, sire, and siblings from previous litters, and the early Mori, Y. 2004. Breed differences in genotype and allele fre- quency of catechol O-methyltransferase gene polymorphic environment during the socialization period, as has been regions in dogs. J. Vet. Med. Sci. 66: 183–187. repeatedly emphasized in previous studies [5, 7, 8]. 14. Masuda, K., Hashizume, C., Ogata, N., Kikusui, T., Takeuchi, Y. and Mori, Y. 2004. Sequencing of canine 5-hydrox- ACKNOWLEDGMENTS. We thank all veterinarians who ytriptamine receptor (5-HTR) 1B, 2A, 2C genes and identifica- participated in this survey, especially DVMs Shoji Satoh, tion of polymorphisms in the 5-HTR1B gene. J. Vet. Med. Sci. Keiko Uchida, and Yoshiko Uchida for recruiting respon- 66: 965–972. dents from among their colleagues and Drs. Benjamin and 15. Nara, H., Inoue-Murayama, M., Koshimura, A., Sugiyama, A., Lynette Hart, and Dr. John Bradshaw for permission to use Murayama, Y., Maejima, M., Ueda, Y., Ito, H., Randi, E., Kim, 796 Y. TAKEUCHI AND Y. MORI

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