|
|
Flauger, B., Möstl, E., & Krueger., K. (2012). The introduction of horses into new groups: Social interactions and cortisol release. In K. Krueger (Ed.), Proceedings of the 2. International Equine Science Meeting (Vol. in press). Wald: Xenophon Publishing.
Abstract: Domestic horses are kept in so-called “fate societies” where they have to deal with frequent mixing. Several studies have evaluated and discussed the aggression level and injury risk during the introduction of horses into new groups, but nothing is known about the endocrine responses and thus if horses experience stress during introduction.
In this study we analysed the efficiency of four approved introduction techniques and evaluated the introduction of 30 horses into 11 different groups. Horses were introduced: 1) immediately, 2) after observing the new group for several days, 3) together with an “integration horse” after several days of observation, or 4) with a mixed strategy. Aggressive as well as positive social behaviour between the introduced horses and the group members were analysed the two hours following the introduction event. In addition, we focussed on the glucocorticoid production of the newcomer horses by measuring faecal cortisol metabolites (FCM) on the day of the introduction as well as the following three days.
For the four introduction techniques we found significant differences in the horses’ aggressive and submissive behaviour as well as in their total interactions. The introduction together with an integration horse led to significantly lower levels of aggression and less total interactions than the immediate introduction of single horses.
Horses which were introduced immediately or after an observation period showed significantly elevated levels of FCM on the first, second and third day after the introduction. For horses introduced together with an integration horse FCM were already significantly higher on the day of the introduction, indicating a stressful event before the introduction itself. In contrast, FCM levels were always very low when using the mixed technique.
In sum, horses have the ability to deal with conflict when they are introduced to new group members. The introduction event itself appears not to be as stressful as previously assumed. Standing together with an “integration horse” on a separate paddock and not being able to integrate immediately into a new group appears to be stressful for the newcomer. Based on the findings of our study we suggest to introduce new horses in group management together with a new group mate, a so-called “integration horse”. This would reduce the number of total social interactions as well as the aggression level. While this technique may be stressful for the newcomer, it lowers aggressive behaviour between the introduced horse and the group members and consequently reduces injury risks.
|
|
|
|
Fureix, C., Bourjade, M., Henry, S., Sankey, C., & Hausberger, M. (2012). Exploring aggression regulation in managed groups of horses Equus caballus. Appl. Anim. Behav. Sci., 138(3–4), 216–228.
Abstract: Horses are highly social animals that have evolved to live in social groups. However, in modern husbandry systems, single housing prevails where horses experience social isolation, a challenge-to-welfare factor. One major reason for this single housing is the owners’ concerns that horses may injure each other during aggressive encounters. However, in natural conditions, serious injuries due to aggressive encounters are rare. What could therefore explain the claimed risks of group living for domestic horses? Basing our questioning on the current knowledge of the social life of horses in natural conditions, we review different practices that may lead to higher levels of aggression in horses and propose practical solutions. Observations of natural and feral horses mostly indicate a predominance of low frequencies and mild forms of aggression, based on subtle communication signals and ritualized displays and made possible by group stability (i.e. stable composition), dominance hierarchy and learning of appropriate social skills by young horses. Obviously, adults play a major role here in canalizing undesirable behaviours, and social experience during development, associated with a diversity of social partners, seems to be a prerequisite for the young horse to become socially skilled. Given the natural propensity of horses to have a regulation of aggression in groups, the tendency to display more aggression in groups of domestic horses under some management practices seems clearly related to the conditions offered. We therefore review the managing practices that could trigger aggressiveness in horses. Non social practices (space, resource availability) and social practices (group size, stability of membership, composition and opportunities for social experiences during development) in groups of domestic horses are discussed here. Finally, we propose simple practical solutions leading to more peaceful interactions in groups of domestic horses, based on the knowledge of horses’ natural social life which therefore should be enhanced (e.g. ensuring roughage availability, favouring group stability, introducing socially experienced adults in groups of young horses, etc.). The state of the art indicates that many questions still need to be answered. Given the importance of the associated welfare issues and the consequences on the use of horses, further research is required, which could benefit horses… and humans.
|
|
|
|
Austin, N. P., & Rogers, L. J. (2012). Limb preferences and lateralization of aggression, reactivity and vigilance in feral horses, Equus caballus. Anim. Behav., 83(1), 239–247.
Abstract: Observational field studies were conducted on two remote populations of feral horses in Australia to determine whether lateralization is a characteristic of Equus caballus as a species or results from handling by humans. Group 1 had been feral for two to five generations and Group 2 for 10–20 generations. In both groups, left-side biases were present during agonistic interactions and in reactivity and vigilance. Therefore, as in other vertebrates, the right hemisphere appears to be specialized to control agonistic behaviour and responses to potential threats. The leftwards bias was stronger in measures of behaviour involving more aggression and reactivity. Preferences to place one forelimb in front of the other during grazing were also determined. No population bias of forelimb preference was found, suggesting that such limb preferences present in domestic horses may be entrained. Since stronger individual limb preferences were found in immature than in adult feral horses, limb preference may be modified by maturation or experience in the natural habitat. Stronger limb preference was associated significantly with elevated attention to the environment but only in younger feral horses. No sex differences in lateralization were found. The findings are evidence that horses show visual lateralization, as in other vertebrates, not dependent on handling by humans. Limb preference during grazing, by contrast, does appear to depend on experience.
|
|
|
|
Obergfell, J. (2012). Einf lus s v on St ruktur e l ement en auf da s Li eg ev e rha l t en v on Pf e rden in Gruppenha l tung unt e r Be rücks i cht igung de s Ag g r e s s i ons v e rha l t ens. Ph.D. thesis, , Karlsruhe.
Abstract: Durch die vorliegende Studie wurde der Einfluss von Strukturelementen auf das Liege- und Aggressionsverhalten von Pferden in Gruppenhaltung untersucht. Die Strukturelemente sollten Rückzugsmöglichkeiten bieten, sowie in ihrem Bereich zur Aufhebung der Individualdistanz führen und dadurch die Fläche relativ vergrößern. Für die Versuche stellte das Haupt- und Landesgestüt Marbach drei unabhängige Pferdegruppen mit verschiedener Herdengröße zur Verfügung, die jeweils in Einraum- Innenlaufställen gehalten wurden. Die Datenerfassung fand zwischen 23 und sieben Uhr statt. Insgesamt wurden 366 Stunden Videomaterial ausgewertet. Beim Ruheverhalten wurden mit Hilfe des event-sampling- Verfahrens die Parameter Gesamtliegedauer, Dauer in Seitenlage, Dauer der Einzelphasen in
Seitenlage und Abliegehäufigkeit pro Nacht erfasst. Es wurden Versuchsphasen ohne
Strukturelemente und mit hängenden Planen als Strukturierung durchgeführt. Im ersten Stall
kamen außerdem über einander gestapelte Strohballen zum Einsatz. Diese Art der
Strukturierung stellte sich jedoch als nicht praktikabel heraus und führte im Vergleich zu den Planen zu einer signifikanten Verschlechterung der Gesamtliegedauer. In Stall 1 konnte man eine tendenzielle Verbesserung der Parameter Gesamtliegedauer und Gesamtdauer in Seitenlage durch das Anbringen von Planen sehen. In Stall 3 dagegen verschlechterte sich das Ruheverhalten in den Versuchsphasen mit Planen gegenüber den Versuchsphasen ohne Struktur. Die Werte der Gesamtdauer in Seitenlage nahmen signifikant ab. In Stall 2 zeigten sich keine Unterschiede in den verschiedenen Versuchsphasen. Möglicherweise ist die Wirkung der Strukturelemente auf das Liegeverhalten abhängig von der Flächengröße. Stall 1 hatte bezogen auf die Leitlinien des BMELV die größte und Stall 3 die kleinste Fläche. Bei den anderen Parametern des Liegeverhaltens gab es keine signifikanten Unterschiede in den verschiedenen Versuchsphasen. Mit Hilfe des time-sampling-Verfahrens wurde die Anzahl gleichzeitig liegender Pferde und gleichzeitig liegender Pferde in Seitenlage bestimmt. Auch hier zeigten sich keine Unterschiede in den verschiedenen Versuchsphasen. Bei der Gegenüberstellung der Werte der Gesamtliegedauer und der Gesamtdauer in Seitenlage mit dem Alter der Pferde (Stall 1 und Stall 3) und mit dem Integrationszeitpunkt (Stall 1) konnte kein Zusammenhang festgestellt werden. Beim Aggressionsverhalten wurden mit Hilfe des
event-sampling-Verfahrens in den Ställen 2 und 3 verschiedene Arten von Aggressionen
erfasst, die dann in die drei Intensitätsgrade Low-Level-, Mid-Level- und High-Level-
Aggressionen unterteilt wurden. Neben der Anzahl wurde die Dauer der verschiedenen
Aggressionen bewertet. Insgesamt konnte eine positive Wirkung der Planen auf das
Aggressionsverhalten beobachtet werden. Die Gesamtanzahl an Aggressionen nahm in beiden
Ställen tendenziell in den Versuchsphasen mit Planen ab. In Stall 3 konnte, wenn man die
Aggressionen stundenweise betrachtet, ein signifikanter Unterschied festgestellt werden.
Auch der Hinterhandschlag und die Aggressionen, welche das Ruheverhalten stören,
verringerten sich tendenziell nach dem Anbringen von Strukturelementen. In beiden Ställen
nahm die relative Häufigkeit von Mid-Level-Aggressionen nach dem Anbringen von Planen
zu. Dagegen konnte bei den High-Level-Aggressionen und in Stall 3 bei den Low-Level-
Aggressionen eine relative Abnahme beobachtet werden. Sowohl die Anzahl als auch die
Dauer der Mid-Level-Aggressionen verringerten sich in Stall 3 stundenweise betrachtet
signifikant in den Versuchsphasen mit Planen. In Stall 2 war bei den High-Level-
Aggressionen sowohl bei der Dauer als auch bei der Anzahl eine signifikante Abnahme zu
sehen. Wenn man das Aggressionsverhalten in Bezug zu der Fläche in den zwei Ställen
betrachtet, schien diese vor allem einen Einfluss auf die High-Level-Aggressionen zu
nehmen. Mit Hilfe des Rangindex der Pferde im Stall 3 wurde eine Rangordnung aufgestellt.
Zwischen dem Platz der Pferde in der Rangordnung und den Parametern des Ruheverhaltens
(Gesamtliegedauer, Gesamtdauer in Seitenlage) sowie dem Alter der Pferde konnte kein
Zusammenhang festgestellt werden. Zwischen dem Rangindex und der Gesamtanzahl an
Aggressionen bestand dagegen ein hoch signifikanter Zusammenhang. Im Rahmen dieser
Studie ist das Anbringen von Strukturelementen in Bezug auf das Aggressionsverhalten in
Einraum-Innenlaufställen von Pferden zu empfehlen. Die Wirkung auf das Liegeverhalten der
Pferde sollte in weiteren Studien untersucht werden.
[In this study the influence of structural elements on lying and aggression behavior in horses
kept in groups was exanimated. Structural elements should offer the possibility of retreat.
Furthermore, within the respective area, the individual distance should be limited, thus
increasing the overall space relatively. For the studies the “Haupt- und Landesgestüt
Marbach” provided three non-related groups of different sized horses, each kept in separate
“Einraum-Innenlaufställen”. Data collection took place between 11 pm and 7 am. Altogether,
366 hours of video material were analyzed. Using the event-sampling-method, the following
parameters within the horses´ resting behavior were determined: The total lying period, the
total lying period in lateral position, the periods of the single lying in lateral position and the
frequency of lying down. Test phases were carried out without structural elements and with
hanging canvases as structural elements. In the first stable there were also three bales of straw
piled up on top of each other. This kind of structuring emerged as impractical and in
comparison to the canvas, led to a significant deterioration to the total period of lying. After
the canvases were fixed in the first stable, a slight improvement with the parameters of total
lying period and total lying period in the lateral position could be seen. In contrast, the resting
behavior in stable 3 worsened in the test phases with the canvases in comparison to the test phases without structural elements. The values for the total lying period in the lateral position
decreased significantly. In stable 2, there were no differences in the different test phases.
Possibly the effect of the structural elements is dependent of the space. Stable 1 had the
largest space and stable 3 the least space referred to the guideline of the BMELV. The other
parameters of the lying behavior showed no significant differences in the different test phases.
The number of horses lying at the same time, and the number of horses lying at the same time
in the lateral position were detected with the aid of the time-sampling-method. There were
also no differences between the different test phases. If the values of the total lying period and
the total lying period in lateral position were compared to the age of the horses (stable 1 and
stable 3) and to the point of integration (stable 1), there was no correlation.
Different kinds of aggression were detected by the means of the event-sampling-method in
stable 2 and 3 and were subdivided into the three levels of intensity: Low-level-, mid-level
and high-level-aggressions. Both the number and the duration of the different aggressions
were evaluated. All in all a positive influence of the canvas on the aggression behavior could
be observed. In both stables, the total number of aggressions decreased in the test phases with
canvases. In stable 3 a significant difference could be detected, if the aggressions were
observed per hour. Also hind limb kicks and aggressions disturbing the resting behavior,
decreased by trend, after fixing the canvases in the stable. In both stables the relative
frequency of mid-level-aggressions increased after the canvases were mounted. In contrast
there was a relative decrease at the high-level-aggressions and in stable 3 at the low-levelaggressions.
The number and the duration of the mid-level-aggressions in stable 3 decreased,
when considered by the hour in the test phases with canvases. In stable 2 a significant
decrease in duration and number of high-level-aggressions was observed. When examining
aggression behavior in reference to space in the two stables, high-level-aggressions seemed to
be mostly influenced. In stable 3 a rank order was established with the aid of the rank index of
the horses. There was no correlation between the horses´ rank and the parameters of the
resting behavior (the total lying period, the total lying period in lateral position) and between
horses´ rank and age. In contrast, there was a high significant correlation between the rank
index and the total number of aggressions. In context to this study, structural elements in
“Einraum-Innenlaufställen” (BMELV 2009) seem to have a positive influence on the
aggression behavior and thus seem to be recommendable. The influence on the lying behavior
should be investigated in further studies.]
Keywords: Pferde, Ruheverhalten, Liegeverhalten, Aggressionsverhalten, Strukturelemente, Rangordnung [horses, rest behavior, lying behavior, aggression behavior, structural elements, rank order]
|
|
|
|
Ahrendt, L. P., Christensen, J. W., & Ladewig, J. (2012). The ability of horses to learn an instrumental task through social observation. In Applied Animal Behaviour Science (Vol. 139, pp. 105–113).
Abstract: The ability of horses to learn through social observation may ease the implementation of new management systems, because the use of automatic feeders etc. by naive horses could be facilitated by observation of experienced horses. However, previous studies found no documentation for observational learning abilities in horses. This study aimed to investigate the ability of horses to learn an instrumental task from a familiar conspecific when social interaction was allowed during the demonstration. Two similar experiments were performed. In the first experiment, Observer horses (n=11) participated in ten successive demonstrations, where a trained Demonstrator opened an operant device by pushing a sliding lid aside with the muzzle in order to obtain a food reward. Immediately after the demonstrations the Observer horses were given the opportunity to operate the device alone. Control horses (n=11) were aware that the device contained food but were presented to the operant device without demonstration of the task. The learning criterion was at least two openings. Accomplishment of and latency to accomplish the learning criterion, and investigative behaviour towards the operant device were recorded. Five Observers and one Control, out of the eleven horses in each treatment group, accomplished the learning criterion. Even though this presents a high odds ratio (OR) in favour of the Observer treatment (OR=7.6), there was no significant difference between the treatment groups (P=0.15). Analysis of investigative behaviour showed, however, that the demonstrations increased the motivation of the Observer horses to investigate the device. Subsequently, a similar experiment was performed in a practical setting with 44 test horses (mixed age, gender and breed). We used the same operant device and the same number and type of demonstrations, although the horses were held on a loose rope to minimise aggression. In this second experiment, six of 23 Observer horses and five of 21 Control horses learned the instrumental task, representing no influence of the demonstration. Thus, this study did not demonstrate an ability of horses to learn an instrumental task through observation.
|
|
|
|
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.]
|
|
|
|
Calcagnoli, F., Boer, S. F., Althaus, M., Boer, J. A., & Koolhaas, J. M. (2013). Antiaggressive activity of central oxytocin in male rats. Psychopharmacology, 229(4), 639–651.
Abstract: Rationale A substantial body of research suggests that the
neuropeptide oxytocin promotes social affiliative behaviors
in a wide range of animals including humans. However, its
antiaggressive action has not been unequivocally demonstrated
in male laboratory rodents.
Objective Our primary goal was to examine the putative
serenic effect of oxytocin in a feral strain (wild type
Groningen, WTG) of rats that generally show a much
broader variation and higher levels of intermale aggression
than commonly used laboratory strains of rats.
Methods Resident animals were intracerebroventricularly
(icv) administered with different doses of synthetic oxytocin
and oxytocin receptor antagonist, alone and in combination,
in order to manipulate brain oxytocin functioning and to
assess their behavioral response to an intruder.
Results Our data clearly demonstrate that acute icv administered
oxytocin produces dose-dependent and receptorselective
changes in social behavior, reducing aggression
and potentiating social exploration. These antiaggressive
effects are stronger in the more offensive rats. On the other
hand, administration of an oxytocin receptor antagonist
tends to increase (nonsignificantly) aggression only in
low–medium aggressive animals.
Conclusions These results suggest that transiently enhancing
brain oxytocin function has potent antiaggressive effects,
whereas its attenuation tends to enhance aggressiveness. In
addition, a possible inverse relationship between trait aggression
and endogenous oxytocinergic signaling is revealed.
Overall, this study emphasizes the importance of brain
oxytocinergic signaling for regulating intermale offensive aggression.
This study supports the suggestion that oxytocin
receptor agonists could clinically be useful for curbing heightened
aggression seen in a range of neuropsychiatric disorders
like antisocial personality disorder, autism, and addiction.
|
|
|
|
Austin, N. P., & Rogers, L. J. (2014). Lateralization of agonistic and vigilance responses in Przewalski horses (Equus przewalskii). Applied Animal Behaviour Science, 151, 43–50.
Abstract: tEye and limb preferences were scored in the closest undomesticated relative of Equuscaballus using the same methods as used previously to study laterality in feral horses.Observations were made of 33 Przewalski horses (Equus ferus przewalskii) (male N = 20,female N = 13) living under natural social conditions on a large reserve in France. Signifi-cant left-eye/side biases were found in agonistic interactions within harem bands (M ± SEbias to left 58% ± 0.01 for threats, P < 0.001; 68% ± 0.05 for attacks; P < 0.001) and in stallionfights (threats, 52% ± 0.01 left, P < 0.001; attacks, 63% ± 0.02 left, P < 0.001): as many as 80%of the horses were significantly lateralized in attack responses within harem bands. Lat-erality of vigilance was measured as lifting up the head from grazing and turning it to theleft or right side: a directional bias to the left was found (M ± SE 53% ± 0.02 left, P < 0.001).Side bias in reactivity was calculated as the percent of head lifts above the level of thewithers on the left or right side and this was also left side biased (M ± SE 73% ± 0.03 left,P < 0.001). These results indicate right-hemisphere specialization for control of aggressionand responses to novelty. The left bias in attack scores within harem bands was strongerin males than females (P = 0.024) and in immature than adult horses (P = 0.032). Immaturehorses were also more strongly lateralized than adults in vigilance scores (P = 0.022), whichmay suggest that experience reduces these side biases. Our results show that Przewalskihorses exhibit left eye preferences, as do feral horses, and do so even more strongly thanferal horses. Considering feral and Przewalski horses together, we deduce that ancestralhorses had similar lateral biases. Also similar to feral horses, the Przewalski horses showedno significant forelimb preference at the group level or in the majority of horses at theindividual level, confirming the hypothesis that previously reported limb preferences indomestic breeds are entrained or generated by breed-specific selection.
|
|
|
|
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.
|
|
|
|
Duboscq, J., Agil, M., Engelhardt, A., & Thierry, B. (2014). The function of postconflict interactions: new prospects from the study of a tolerant species of primate. Anim. Behav., 87, 107–120.
Abstract: Aggression can generate anxiety, create uncertainty about its aftermath and jeopardise social relationships. Postconflict interactions serve as conflict management strategies to mitigate these consequences. Whereas postconflict interactions are well characterized in many animals, their functions are still insufficiently investigated. Four functional hypotheses have been proposed: stress reduction, relationship repair, self-protection and benign intent. We aimed to test these hypotheses in females of a tolerant macaque species, the crested macaque, Macaca nigra, under natural conditions, for three postconflict interactions: reconciliation, affiliation and aggression with third parties. Our results provide meaningful contrasts compared with findings in other species. We found no evidence that aggression had consequences for individuals' behavioural indicators of anxiety, although it increased the likelihood of secondary aggression with third parties. There was little evidence for the stress reduction hypothesis as the occurrence of any of the three postconflict interactions investigated had little effect on the measured behavioural indicators of anxiety. Conflict and dyad characteristics also had limited influence on anxiety. The relationship repair function was only partly validated: dyads with stronger bonds or that exchanged more support did not reconcile more often, but dyads with attributes related to the symmetry, stability and predictability (i.e. security) within relationships did. Patterns of initiation and directionality of postconflict interactions in this study population suggest that reconciliation may constitute the signalling of appeasement and benign intent. Furthermore, we found that aggression towards third parties may serve as a source of self-protection and reassertion of the females' social status. The distinctive pattern of postconflict management strategies revealed in wild female crested macaques appears to be related to their typically tolerant social style. These results demonstrate the usefulness of concomitantly studying aggression, postconflict interactions and their functions, to understand conflict management strategies comprehensively, while taking into account the level of social tolerance characterizing the studied society.
|
|
