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Social play in dogs: Individual variation and change over time
Dogs and other canines in the wild canine or unilateral canine biting. Models were scaled to common size and identical bite forces were simulated. Jaw dimensions among dietary groups differed as predicted, and this result was independent of body size. FEA showed that under both loading conditions, the long, narrow skull of C. simensis was highly stressed and exhibited steep stress gradients. C. mesomelas performed fairly well under bilateral canine biting, but less well under unilateral biting. The skull of L. pictus behaved extremely well under both loads, and the low stresses decreased smoothly from anterior to posterior. It is clear that the short, broad snouts of large vertebrate specialists facilitate large bite forces, but they are also well suited to dealing with the larger and more unpredictable loads associated with this type of prey. The long, narrow snouts of small vertebrate specialists are well suited to catching small prey but are poorly suited to dealing with large loads. It seems that the evolution of morphologies associated with small prey specialization results in performance trade-offs that may limit the ability of these taxa to use other, less favored resources. Key words: skull strength; finite element analysis; Canidae 30 SOCIAL DYNAMICS OF A GROUP OF FREE-RANGING DOMESTIC DOGS LIVING IN A SUBURBAN ENVIRONMENT Simona Cafazzo1,*, Paola Valsecchi1, Claudio Fantini2, Eugenia Natoli2 1 Dipartimento Di Biologia Evolutiva E Funzionale, University of Parma, Italy. 2 Azienda Usl Roma D, Ospedale Veterinario, Roma, Italy. *Corresponding author: [email protected] In westernized countries the presence of stray dogs is forbidden by law and few citizens have more than 2 dogs. Therefore, there are not many canine social groups suitable for behavioral studies, and intraspecific social relationships are poorly understood. Moreover, the possibility that freeranging dogs form stable social group was highly debated. Available literature on the eco-ethology of stray/feral dogs concerns limited-size (1–8 dogs) groups in which the dominance hierarchies and its influences on social dynamics have never been studied systematically. The aim of this study was to analyze the social structure and the spacing pattern of a group of free-ranging dogs (25–40 dogs) that could breed and move freely, but were dependent on human beings for food. Data were collected (April 2005– May 2006) via focal animal sampling and ad lib sampling methods. We tested the transitivity of dominance relationships between members of the social group by applying an improved test of linearity developed by de Vries. We carried out non-parametric statistical tests, two-way and one-way ANOVA. All statistical tests were two-tailed. A linear dominance hierarchy based on direction of agonistic behavior was found. The rank order did not change in different contexts (in the presence of food, receptive females or in the absence of sources of competition). Frequency of
61 agonistic behaviors was higher in the presence of receptive females and even higher in the presence of food (c2 5 17.10, d.f. 5 2, n 5 16, P , 0.001). The home range of the group was calculated using the minimum convex polygon method and measured 61 hectares. Group members cooperated during territorial defense against intruders. The size of the territory was smaller than 61 hectares; in fact boundaries of the area defended were inside the boundaries of the home range. Urine marking and ground-scratching behaviors were associated with territorial defense and were influenced by social status: high-ranking dogs marked more often than low-ranking dogs (rs 5 0.91, n 5 27, P , 0.001). Dominance rank and familiarity between males and females influenced mate choice: adult females preferred high-ranking males whereas young females preferred familiar males. Adult high-ranking females were courted more than young low-ranking females. Individuals belonging to this group cooperated for territorial defense and some males helped females in pup defense. Dogs’ sociality seems to be more complex than asserted recently. In spite of the process of domestication and the effects of artificial selection, this group of dogs behaved adaptively. In fact, in the presence of an abundant food source, dogs can form social groups that are similar in structure and dynamics to those of other species of canids. Key words: Canis lupus familiaris; dominance hierarchy; home range; mate choice; territorial behavior 31 SOCIAL PLAY IN DOGS: INDIVIDUAL VARIATION AND CHANGE OVER TIME Camille Ward*, Barbara B. Smuts Department of Psychology, University of Michigan, Ann Arbor, MI *Corresponding author: Camille Ward: [email protected] Our ethological research on social play among dogs has documented consistent patterns in both adult and puppy populations (Bauer and Smuts, 2007; Ward et al., 2008). For example we measured asymmetry within dyads in terms of top dog versus underdog roles and who controlled access to dog toys. Although researchers have asserted that play must be fair for it to continue (‘‘50:50 rule’’), neither adults nor puppies conformed to this prediction. However, in a few relationships, play was consistently fair, and in others, the degree of fairness changed over time. We used long-term observations of several dyads to investigate such variations in detail. We studied 4 dyads: one set involved a male German shepherd dog (Sage), aged 7 weeks at the start of observations, playing with 2 housemates, a 5-year-old female Doberman pinscher (Acorn) and a 8-year-old male Labrador retriever (Marty), plus Sage and a frequent playmate, a Labrador retriever-poodle mix (Sam). We also observed play between a young adult male (Tex) and an older female housemate (Tasha), mixed breeds of the same size. We videotaped dyadic play in a variety of settings for up to 31
62 months. We calculated asymmetries in play based on protocols used in our earlier studies (Bauer and Smuts, 2007) and determined divergence from 50:50 within dyads using the binomial test (2-tailed). Housemates Acorn/Sage and Marty/Sage followed a similar pattern: initially play was asymmetrical with the adult dog ‘‘winning’’ most play events (P , 0.05 for both dyads), but when Sage reached adolescence (6-9 months), this situation switched and Sage won most often (P , 0.05 for both dyads). However, by the time Sage reached adulthood, play between Sage and each housemate conformed to the 50:50 rule and was still fair 1 year later (P . 0.05 for both dyads). In contrast, Sage won over Sam from the beginning, and nearly 3 years later, he still does (P , 0.05). In the fourth dyad, most play involved access to toys. Initially Tasha controlled all access (P , 0.05), but over several months, access gradually became equal and remained so (P . 0.05). These findings suggest that: (1) interesting patterns emerge when play is studied at the dyadic level; (2) asymmetry of play roles within dyads can be very fluid over time; (3) a given dog can show different patterns of asymmetry depending on the partner’s identity; and (4) although most dyads play asymmetrically, perhaps dogs living together are the ones most likely to end up playing fairly. Testing this hypothesis requires labor-intensive studies of how dog–dog relationships form and change over time. Key words: social play; dogs; social relationships
References Bauer, E.B., Smuts, B.B., 2007. Cooperation and competition during dyadic play in domestic dogs, Canis familiaris. Anim. Behav 73, 489–499. Ward, C., Bauer, E.B., Smuts, B.B., 2008. Partner preferences and asymmetries in social play among domestic dog, Canis lupus familiaris, littermates. Anim. Behav 76, 1187–1199.
32 DOG LITTER IN AN URBAN ENVIRONMENT: FACTORS ASSOCIATED WITH OWNERS’ DECISION NOT TO PICK UP THEIR DOGS’ DROPPINGS Christine Arhant* Josef Troxler Institute of Animal Husbandry and Animal Welfare, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Wien, Austria *Address for reprint requests and correspondence: Christine Arhant: [email protected] The presence of man’s best friend in cities can create a nuisance and lead to increased hygiene risks owing to feces left in public areas. Our aim was to identify the characteristics of Viennese dog owners who do not pick up their dogs’ feces. In January 2007, we sent a questionnaire by post and asked owners for their and their dogs’ demographic information and whether they did or did not pick up feces deposited by
Journal of Veterinary Behavior, Vol 4, No 2, March/April 2009 their dogs in public places. For insight into owner personality, we used the TIPI-G (Muck et al., 2007). A total of 1370 people returned questionnaires, which were analyzed using the Mann-Whitney U test and cross-tabulations. Of responding owners, 56.2% stated that they clean up after their companion, and 41.1% reported that they only sometimes or never picked up their dog’s droppings. Members of the latter group were male more often than expected by chance alone (c2 5 26.15, P 5 0.001); they also were younger (Z 5 -5.32, P 5 0.001) and were less likely to live in a 1-person household (c2 5 12.31, P 5 0.000). A higher proportion lived with children (c2 5 18.80, P 5 0.001) and were employed (c2 5 21.21, P 5 0.001). They rate themselves as being less agreeable (Z 5 -3.33, P 5 0.001), less conscientious (Z 5 -5.06, P 5 0.001), less open to experience (Z 5 -2.87, P 5 0.004) and disagreed more often with the statements: ‘‘It is important for me that other peoples’ perception of my dog is positive’’ (c2 5 19.53, P 5 0.001) and ‘‘I wish for a positive attitude toward dogs and their owners in Vienna’’ (c2 5 11.65, P 5 0.001). ‘‘Non-picking-up-owners’’ reported a domicile in the inner districts of Vienna less frequently (c2 5 35.42, P 5 0.001), owned heavier dogs (Z 5 -4.08, P 5 0.000) and spent less time petting and walking them (Z 5 -4.63, P 5 0.001). A higher proportion of their dogs were walked without a leash (c2 5 11.32, P 5 0.001), but no differences were found in the dogs’ reported behaviors. As expected, owner attitudes and environmental conditions affect the decision for cleaning up. In contrast to previous studies, we found significant differences between demographics and personality of responsible and irresponsible owners (Webley and Siviter, 2000). Disgust of or distaste for the task is believed to be a factor for not picking up. This hypothesis is supported given that the feces of heavier dogs were picked up less often, but is contradicted by further findings: disgust sensitivity is more pronounced in women and is positively correlated with agreeableness and conscientiousness (Druschel and Sherman, 1999). We consider that disgust for feces left in public areas possibly outweighs the distaste for picking it up, since a higher proportion of women and owners scoring high for agreeableness and conscientiousness reported cleaning up after their dog. Key words: dog litter; urban dogs; dog–human interactions; personality; disgust
References Druschel, B.A., Sherman, M.F., 1999. Disgust sensitivity as a function of the Big Five and gender. Personality and Individual Differences 26, 739–748. Muck, P., Hell, B., Gosling, S.D., 2007. Construct validation of a short fivefactor model instrument: a self-peer study on the German adaptation of the Ten-Item Personality Inventory (TIPI-G). European Journal of Psychological Assessment 23, 166–175. Webley, P., Siviter, C., 2000. Why do Some Owners allow their Dogs to Foul the Pavement? J. Appl. Soc. Psychol 30, 1371–1380.
61 agonistic behaviors was higher in the presence of receptive females and even higher in the presence of food (c2 5 17.10, d.f. 5 2, n 5 16, P , 0.001). The home range of the group was calculated using the minimum convex polygon method and measured 61 hectares. Group members cooperated during territorial defense against intruders. The size of the territory was smaller than 61 hectares; in fact boundaries of the area defended were inside the boundaries of the home range. Urine marking and ground-scratching behaviors were associated with territorial defense and were influenced by social status: high-ranking dogs marked more often than low-ranking dogs (rs 5 0.91, n 5 27, P , 0.001). Dominance rank and familiarity between males and females influenced mate choice: adult females preferred high-ranking males whereas young females preferred familiar males. Adult high-ranking females were courted more than young low-ranking females. Individuals belonging to this group cooperated for territorial defense and some males helped females in pup defense. Dogs’ sociality seems to be more complex than asserted recently. In spite of the process of domestication and the effects of artificial selection, this group of dogs behaved adaptively. In fact, in the presence of an abundant food source, dogs can form social groups that are similar in structure and dynamics to those of other species of canids. Key words: Canis lupus familiaris; dominance hierarchy; home range; mate choice; territorial behavior 31 SOCIAL PLAY IN DOGS: INDIVIDUAL VARIATION AND CHANGE OVER TIME Camille Ward*, Barbara B. Smuts Department of Psychology, University of Michigan, Ann Arbor, MI *Corresponding author: Camille Ward: [email protected] Our ethological research on social play among dogs has documented consistent patterns in both adult and puppy populations (Bauer and Smuts, 2007; Ward et al., 2008). For example we measured asymmetry within dyads in terms of top dog versus underdog roles and who controlled access to dog toys. Although researchers have asserted that play must be fair for it to continue (‘‘50:50 rule’’), neither adults nor puppies conformed to this prediction. However, in a few relationships, play was consistently fair, and in others, the degree of fairness changed over time. We used long-term observations of several dyads to investigate such variations in detail. We studied 4 dyads: one set involved a male German shepherd dog (Sage), aged 7 weeks at the start of observations, playing with 2 housemates, a 5-year-old female Doberman pinscher (Acorn) and a 8-year-old male Labrador retriever (Marty), plus Sage and a frequent playmate, a Labrador retriever-poodle mix (Sam). We also observed play between a young adult male (Tex) and an older female housemate (Tasha), mixed breeds of the same size. We videotaped dyadic play in a variety of settings for up to 31
62 months. We calculated asymmetries in play based on protocols used in our earlier studies (Bauer and Smuts, 2007) and determined divergence from 50:50 within dyads using the binomial test (2-tailed). Housemates Acorn/Sage and Marty/Sage followed a similar pattern: initially play was asymmetrical with the adult dog ‘‘winning’’ most play events (P , 0.05 for both dyads), but when Sage reached adolescence (6-9 months), this situation switched and Sage won most often (P , 0.05 for both dyads). However, by the time Sage reached adulthood, play between Sage and each housemate conformed to the 50:50 rule and was still fair 1 year later (P . 0.05 for both dyads). In contrast, Sage won over Sam from the beginning, and nearly 3 years later, he still does (P , 0.05). In the fourth dyad, most play involved access to toys. Initially Tasha controlled all access (P , 0.05), but over several months, access gradually became equal and remained so (P . 0.05). These findings suggest that: (1) interesting patterns emerge when play is studied at the dyadic level; (2) asymmetry of play roles within dyads can be very fluid over time; (3) a given dog can show different patterns of asymmetry depending on the partner’s identity; and (4) although most dyads play asymmetrically, perhaps dogs living together are the ones most likely to end up playing fairly. Testing this hypothesis requires labor-intensive studies of how dog–dog relationships form and change over time. Key words: social play; dogs; social relationships
References Bauer, E.B., Smuts, B.B., 2007. Cooperation and competition during dyadic play in domestic dogs, Canis familiaris. Anim. Behav 73, 489–499. Ward, C., Bauer, E.B., Smuts, B.B., 2008. Partner preferences and asymmetries in social play among domestic dog, Canis lupus familiaris, littermates. Anim. Behav 76, 1187–1199.
32 DOG LITTER IN AN URBAN ENVIRONMENT: FACTORS ASSOCIATED WITH OWNERS’ DECISION NOT TO PICK UP THEIR DOGS’ DROPPINGS Christine Arhant* Josef Troxler Institute of Animal Husbandry and Animal Welfare, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Wien, Austria *Address for reprint requests and correspondence: Christine Arhant: [email protected] The presence of man’s best friend in cities can create a nuisance and lead to increased hygiene risks owing to feces left in public areas. Our aim was to identify the characteristics of Viennese dog owners who do not pick up their dogs’ feces. In January 2007, we sent a questionnaire by post and asked owners for their and their dogs’ demographic information and whether they did or did not pick up feces deposited by
Journal of Veterinary Behavior, Vol 4, No 2, March/April 2009 their dogs in public places. For insight into owner personality, we used the TIPI-G (Muck et al., 2007). A total of 1370 people returned questionnaires, which were analyzed using the Mann-Whitney U test and cross-tabulations. Of responding owners, 56.2% stated that they clean up after their companion, and 41.1% reported that they only sometimes or never picked up their dog’s droppings. Members of the latter group were male more often than expected by chance alone (c2 5 26.15, P 5 0.001); they also were younger (Z 5 -5.32, P 5 0.001) and were less likely to live in a 1-person household (c2 5 12.31, P 5 0.000). A higher proportion lived with children (c2 5 18.80, P 5 0.001) and were employed (c2 5 21.21, P 5 0.001). They rate themselves as being less agreeable (Z 5 -3.33, P 5 0.001), less conscientious (Z 5 -5.06, P 5 0.001), less open to experience (Z 5 -2.87, P 5 0.004) and disagreed more often with the statements: ‘‘It is important for me that other peoples’ perception of my dog is positive’’ (c2 5 19.53, P 5 0.001) and ‘‘I wish for a positive attitude toward dogs and their owners in Vienna’’ (c2 5 11.65, P 5 0.001). ‘‘Non-picking-up-owners’’ reported a domicile in the inner districts of Vienna less frequently (c2 5 35.42, P 5 0.001), owned heavier dogs (Z 5 -4.08, P 5 0.000) and spent less time petting and walking them (Z 5 -4.63, P 5 0.001). A higher proportion of their dogs were walked without a leash (c2 5 11.32, P 5 0.001), but no differences were found in the dogs’ reported behaviors. As expected, owner attitudes and environmental conditions affect the decision for cleaning up. In contrast to previous studies, we found significant differences between demographics and personality of responsible and irresponsible owners (Webley and Siviter, 2000). Disgust of or distaste for the task is believed to be a factor for not picking up. This hypothesis is supported given that the feces of heavier dogs were picked up less often, but is contradicted by further findings: disgust sensitivity is more pronounced in women and is positively correlated with agreeableness and conscientiousness (Druschel and Sherman, 1999). We consider that disgust for feces left in public areas possibly outweighs the distaste for picking it up, since a higher proportion of women and owners scoring high for agreeableness and conscientiousness reported cleaning up after their dog. Key words: dog litter; urban dogs; dog–human interactions; personality; disgust
References Druschel, B.A., Sherman, M.F., 1999. Disgust sensitivity as a function of the Big Five and gender. Personality and Individual Differences 26, 739–748. Muck, P., Hell, B., Gosling, S.D., 2007. Construct validation of a short fivefactor model instrument: a self-peer study on the German adaptation of the Ten-Item Personality Inventory (TIPI-G). European Journal of Psychological Assessment 23, 166–175. Webley, P., Siviter, C., 2000. Why do Some Owners allow their Dogs to Foul the Pavement? J. Appl. Soc. Psychol 30, 1371–1380.