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Judge, P. G., de Waal, F. B., Paul, K. S., & Gordon, T. P. (1994). Removal of a trauma-inflicting alpha matriline from a group of rhesus macaques to control severe wounding. Lab Anim Sci, 44(4), 344–350.
Abstract: Wounding in an 83-member group of rhesus macaques (Macaca mulatta) housed at the Yerkes Regional Primate Research Center Field Station became excessive to the point that intervention was deemed necessary. When observations indicated that three females from the group's alpha matriline were principally responsible for the wounding, the matriline (N = 7) was removed from the group. This study was conducted to document an atypical pattern of wounding in this group and to evaluate the effectiveness of removal as a procedure for controlling injuries. The aggression rates of 21 adult subjects and the wounds of all group members were recorded before and after the removal procedure and compared with those in a similar-sized group. Removing the alpha matriline did not alter aggression rates in the group or the rank order among the remaining matrilines. Aggression rates in the experimental group were also not significantly different from those in the comparison group before or after the removal. With the alpha matriline present, wounding levels in the group were significantly higher than those in the comparison group. After removal of the matriline, the frequency of wounds decreased significantly to levels similar to those of the comparison group. The pattern of excess wounding attributed to the extracted alpha females was idiosyncratic, involving removal of large patches of skin from the hindquarters of adult females or removal of the distal portion of the fingers, toes, or tail from juveniles.(ABSTRACT TRUNCATED AT 250 WORDS)
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Cloutier, S., Newberry, R. C., & Honda, K. (2004). Comparison of social ranks based on worm-running and aggressive behaviour in young domestic fowl. Behav. Process., 65(1), 79–86.
Abstract: Worm-running is behaviour in which a chick runs carrying a worm-like object while flock mates follow and attempt to grab the object from its beak. We hypothesised that social ranks based on worm-running frequency are stable over time and are positively correlated with social ranks based on success in aggressive interactions when older. At 8-12 days of age, we scored worm-running in 17 groups of 12 female White Leghorn chicks during three 10-min tests. Based on instantaneous scans at 5-s intervals, the bird carrying the `worm' most often was placed in rank one and so on down the rank order. These tests were repeated at 68-70 days of age. An aggression index for each bird was calculated as the number of aggressive acts given, divided by the number given and received, during three 1-h observation periods when the birds were 68-70 days. Ranks obtained in worm-running tests were positively correlated over the two age periods (P<0.05) but were not correlated with ranks based on the aggression index (P>0.05). Our results indicate that worm-running ranks are not predictive of success in aggressive interactions. Instead, worm-running fits some criteria for play.
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Li, C., Jiang, Z., Tang, S., & Zeng, Y. (2007). Influence of enclosure size and animal density on fecal cortisol concentration and aggression in Pere David's deer stags. Gen Comp Endocrinol, 151(2), 202–209.
Abstract: We investigated the impact of enclosure size and animal density on behavior and adrenocortical secretion in Pere David's deer in Dafeng Nature Reserve, China. From February 15 to April 16 in 2004, we conducted two experiments. First, we studied maintenance behavior and conflict behavior of Pere David's deer stags in a large enclosure (200 ha) with low animal density (0.66 deer/ha) and a small display pen (0.75 ha) with high animal density (25.33 deer/ha). The maintenance behavior we recorded included standing, locomotion, foraging and rest. During the behavioral observations, we collected fresh voided fecal samples from the stags periodically, and analyzed the fecal cortisol concentrations in those samples using radioimmunoassay technique. Second, we monitored the fecal cortisol concentrations of one group of stags (12 deer lived in an enclosure of 100 ha) before and after transferred into a small pen (0.5 ha). We found that in the first experiment: (1) there were significant differences in standing and rest whereas no significant differences of locomotion and foraging between the free-ranging group and the display group; (2) frequency of conflict behavior in the display group was significantly higher than those in the free-ranging group; and (3) fecal cortisol concentration of the display group (326.17+/-16.98 ng/g dry feces) was significantly higher than that of the free-ranging group (268.98+/-15.21 ng/g dry feces). In the second experiment, there was no significant difference of the fecal cortisol concentrations among sampling days, but the mean fecal cortisol concentration of the day after transferring (337.46+/-17.88 ng/g dry feces) was significantly higher than that of the day before transferring (248.44+/-7.99 ng/g dry feces). Comparison with published findings, our results indicated that enclosure size and animal density affect not only behaviors, but also adrenocortical secretion in Pere David's deer. Small living space with high animal density may impose physiological stress to captive Pere David's deer. Moreover, long-term physiological stress and increase of conflict behavior may subsequently affect survival and reproduction of the deer.
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Sigurjónsdóttir, H., & Haraldsson, H. (2019). Significance of Group Composition for the Welfare of Pastured Horses. Animals, 9(14).
Abstract: We explore how herd composition and management factors correlate with frequencies of social interactions in horse groups. Since the welfare of horses correlates with low aggression levels and social contact opportunities, information of this kind is important. The data are a collection of records of social interactions of 426 Icelandic horses in 20 groups of at least eight horses. The complexities and limitations of the data prohibit useful statistical modelling so the results are presented descriptively. Interesting and informative patterns emerge which can be of use both in management and in future studies. Of special interest are the low levels of agonistic behaviours in breeding groups where one stallion was present. The horses were less agonistic when in groups with young foals and where group membership was stable. Unfamiliar yearlings in peer groups were especially aggressive. Allogrooming was most frequent in groups with relatively more young horses and in unstable and small groups. Interestingly, the horses allogroomed more if they had few preferred allogrooming partners. The findings show that composition (age/sex) and stability of groups are of great importance with respect to aggression levels and opportunities for establishing bonds.
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Flauger, B., & Krueger, K. (2013). Aggressionslevel und Platzangebot bei Pferden (Equus caballus) [ Aggression level and enclosure size in horses (Equus caballus)]. Pferdeheilkunde, 29(4), 495–504.
Abstract: Viele Pferdebesitzer bevorzugen aus Angst vor aggressiven Interaktionen und Verletzungsgefahr der Tiere untereinander die Einzelhaltung, obwohl von Tierschutzorganisationen die Gruppenhaltung für Pferde empfohlen wird. In dieser Studie beobachteten wir während des alltäglichen Soziallebens als auch bei der Eingliederung von neuen Gruppenmitgliedern das Sozialverhalten, insbesondere das Aggressionsverhalten, von elf Gruppen domestizierter Pferde (Equus caballus) verschiedener Größe und Zusammensetzung. Während des alltäglichen Soziallebens hatten die Gruppe und der Paddock-Typ (Gras / kein Gras) keinen Einfluss auf die Verhaltensweisen, wohingegen die Paddockgröße unter 10000 m2 einen signifikanten Einfluss auf die submissiven Verhaltensweisen (GzLM; n=56; t=-2.061, P=0.044) und einen nicht signifikanten Einfluss auf die aggressiven Verhaltensweisen (GzLM; n=56; t=-1.782, P=0.081) hatte. Allerdings verringerten sich sowohl die aggressiven als auch die submissiven Verhaltensweisen mit steigendem Platzangebot bis zu 10000 m2 (Spearman rank Korrelation; n=56; aggressive Verhaltensweisen: r = -0.313, P = 0.019; submissive Verhaltensweisen: r = -0.328, P = 0.014). Während den Eingliederungen reduzierten sich die Aggressionen pro Stunde mit der Vergrößerung des Platzangebotes (Spearman rank Korrelation; n=28; r=-0.402, P=0.034). Dies zeigte sich noch deutlicher, wenn Beobachtungen mit einem Platzangebot von über 10000 m2 ausgeschlos- sen wurden (Spearman rank Korrelation; n=23; r=-0.549, P=0.007). Während des alltäglichen Soziallebens näherte sich der Aggressionslevel der Nulllinie an, wenn das Platzangebot pro Pferd mehr als 331 m2 betrug. Deshalb empfehlen wir zur Reduzierung des Aggressionslevels und des Verletzungsrisikos von sozial gehaltenen Pferdegruppen ein Platzangebot von mindestens 331 m2 pro Pferd.
[Even though animal welfare organisations propose group housing for horse welfare, many owners stable horses individually for fear of aggressive interactions and injury risks. In the present study we observed social behaviour, and especially aggressiveness, in eleven domestic horse groups (Equus caballus) of different size and composition, in basic social situations and when new group members were introduced. During basic social situations, the group and the type of paddock (grass / no grass) had no effect on any of the behaviours, where- as the enclosure size below 10,000 m2 had a significant effect on submissive behaviour (GzLM; n=56; t=-2.061, P=0.044) and an insignificant effect on aggressive behaviour (GzLM; n=56; t=-1.782, P=0.081). However, aggressive and submissive behaviour dimi- nished with the increase of enclosure sizes up to 10,000 m2 (Spearman rank correlation; n = 56; aggressive behaviour: r = -0.313, P=0.019; submissive behaviour: r=-0.328, P=0.014). During introductions, aggression levels per hour decreased with any increase of enclosure size (Spearman rank correlation; n=28; r=-0.402, P=0.034) and even more when enclosure sizes above 10,000 m2 were excluded (Spearman rank correlation; n=23; r=-0.549, P=0.007). During basic social situations the aggression level approached zero when the space allowance was more than 331 m2 per horse. We therefore recommend keeping horse groups in an enclosure with at least 331 m2 per horse to reduce aggression and injuries.]
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Jennings, D. J. (2014). Limited evidence that visual lateralization is associated with fitness in rutting male fallow deer. Anim. Behav., 92, 85–91.
Abstract: Under certain models of animal competition, individuals are expected to gather information about opponent quality in order to determine whether they should fight or withdraw. However, the ability to process complex information differs between individuals and across brain hemispheres: a feature of vertebrate cognition known as lateralization that is not anticipated by contest models. I investigated the relationship between aggressive behaviour and mating success during the fallow deer, Dama dama, rut and a measure of lateralization derived from eye preference during parallel walking. Results show that there was no relationship between the tendency to escalate to fighting or predictability in the tendency to engage in fighting and lateralization. Conversely, there was a quadratic relationship between third-party intervention behaviour and lateralization: the greater the tendency to intervene in ongoing fights the lower the degree of lateralization. However, individuals that showed lateralization for right-eye use were least likely to be targeted by the intervening male; thus lateralization is beneficial in this context because targeted males are highly likely to lose this subsequent encounter. The relationship between lateralization and mating success was also nonlinear: males that showed little evidence for an eye bias during lateral displays had the greatest mating success. Taken together, individuals that showed lateralization benefited from avoiding being targeted after third-party intervention; conversely, individuals that showed little evidence for lateralization actively intervened during ongoing fights and had higher mating success. These results suggest that, although lateralization does appear to confer a fitness advantage on individuals, this is not as extensive as anticipated.
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de Waal, F. B., & Luttrell, L. M. (1986). The similarity principle underlying social bonding among female rhesus monkeys. Folia Primatol (Basel), 46(4), 215–234.
Abstract: Twenty adult female rhesus monkeys (Macaca mulatta) were observed over a three-year period. They lived in a mixed captive group with kinship relations known for three generations. The study's aim was to test Seyfarth's [J. theor. Biol. 65: 671-698, 1977] model of rank-related grooming and to investigate two other possible determinants of social bonding, i.e. relative age and the group's stratification into two social classes. Data on affiliation, coalitions, and social competition were collected by means of both focal observation and instantaneous time sampling. Whereas certain elements of the existing model were confirmed, its explanatory principles were not. Social competition did not result in more contact among close-ranking females (the opposite effect was found), and the relation between affiliative behavior and coalitions was more complex than predicted. Based on multivariate analyses and a comparison of theoretical models, we propose a simpler, more encompassing principle underlying interfemale attraction. According to this 'similarity principle', rhesus females establish bonds with females whom they most resemble. The similarity may concern genetical and social background, age, hierarchical position and social class. Effects of these four factors were independently demonstrated. The most successful model assumed that similarity factors influence female bonding in a cumulative fashion.
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Grosenick, L., Clement, T. S., & Fernald, R. D. (2007). Fish can infer social rank by observation alone. Nature, 445(7126), 429–432.
Abstract: Transitive inference (TI) involves using known relationships to deduce unknown ones (for example, using A > B and B > C to infer A > C), and is thus essential to logical reasoning. First described as a developmental milestone in children, TI has since been reported in nonhuman primates, rats and birds. Still, how animals acquire and represent transitive relationships and why such abilities might have evolved remain open problems. Here we show that male fish (Astatotilapia burtoni) can successfully make inferences on a hierarchy implied by pairwise fights between rival males. These fish learned the implied hierarchy vicariously (as 'bystanders'), by watching fights between rivals arranged around them in separate tank units. Our findings show that fish use TI when trained on socially relevant stimuli, and that they can make such inferences by using indirect information alone. Further, these bystanders seem to have both spatial and featural representations related to rival abilities, which they can use to make correct inferences depending on what kind of information is available to them. Beyond extending TI to fish and experimentally demonstrating indirect TI learning in animals, these results indicate that a universal mechanism underlying TI is unlikely. Rather, animals probably use multiple domain-specific representations adapted to different social and ecological pressures that they encounter during the course of their natural lives.
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Pollard, J. C., & Littlejohn, R. P. (1996). The effects of pen size on the behaviour of farmed red deer stags confined in yards. Appl. Anim. Behav. Sci., 47(3-4), 247–253.
Abstract: To determine whether pen size affected the behaviour and welfare of farmed red deer confined temporarily in yards, four groups of ten 2-year-old stags were confined for 40 min or 2 days in each of spring and summer, in either large (5 m × 4 m ) or small (2.5 m × 4) pens. In the small pens, wall pacing and vertical/horizontal head movements at the walls were more frequently observed (P < 0.05) and were carried out by a greater percentage of the deer (P < 0.001), and distances between individuals were smaller (P < 0.01), than observations in the large pens. Aggressive activities varied seasonally, with head-butting and chasing being seen most frequently in the spring (P < 0.05) and biting and kicking being seen most frequently in the summer (P < 0.05), and the overall frequency of aggressive activities was low in summer. In spring, in small pens there were fewer threats to head-butt, head butts by moving animals, and less stepping activity than in large pens (P < 0.05). In summer, in small pens there were more threats to butt and more stepping activity than in the large pens (P < 0.05). In both seasons, aggressive activities were correlated with wall pacing (r = 0.58 and 0.55, respectively). It was concluded that the effect of pen size on the frequency and nature of aggressive and other activities varied seasonally. In order minimise aggression and stepping activity, small pens were favoured in spring and large pens were favoured in summer. However, in both seasons there were greater inter-individual distances and reduced pacing and head movements at the walls in large pens. This latter finding may indicate that the large pens were less aversive to the deer, regardless of season.
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Dzieweczynski, T. L., Eklund, A. C., & Rowland, W. J. (2006). Male 11-ketotestosterone levels change as a result of being watched in Siamese fighting fish, Betta splendens. Gen Comp Endocrinol, 147(2), 184–189.
Abstract: This study investigated the effects of nesting status and the presence of an audience on 11-ketotestosterone (11KT) levels in male Siamese fighting fish, Betta splendens. Prior studies have demonstrated that both nesting status, an indicator of territory-holding power and reproductive state, and the sex of a conspecific audience lead to differences in male behavior during aggressive encounters. Since behavioral changes have already been demonstrated, we chose to investigate whether 11KT levels were also influenced by nesting status and audience presence as 11KT both stimulates, and is stimulated by, reproductive and aggressive behaviors in male teleosts. Male 11KT levels were measured from water samples taken from containers holding fish both before and after interaction. Males interacted under three treatment conditions: no audience, female audience, and male audience. Within these treatments were two nest paradigms: both males had nests or neither male had a nest. 11KT levels varied depending on nesting status and audience type. In general, 11KT levels were lower in interacting males when a female audience was present or when males had nests. Overall, 11KT showed increases or decreases as aggression increased or decreased, as shown by already established behavioral findings [see Dzieweczynski T.L., Green T.M., Earley R.L., Rowland W.J., 2005. Audience effect is context dependent in Siamese fighting fish, Betta splendens. Behav. Ecol. 16, 1025-1030; Doutrelant, C., McGregor, P.K., Oliveira, R.F., 2001. Effect of an audience on intrasexual communication in male Siamese fighting fish (Betta splendens). Behav. Ecol. 12, 283-286.]. Our results suggest that 11KT levels are influenced by reproductive status, as indicated by nest ownership, and audience presence and are most likely modulated by territorial behavior and social environment.
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