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Majolo, B., Ventura, R., & Koyama, N. F. (2009). A Statistical Modelling Approach to the Occurrence and Timing of Reconciliation in Wild Japanese Macaques. Ethology, 115(2), 152–166.
Abstract: In various social species, animals have been observed to share friendly relationships with some group members and to resolve conflicts through reconciliation, the exchange of affiliative behaviour soon after a conflict that functions to restore the relationship between the former opponents. The valuable relationship hypothesis predicts that reconciliation should be observed more often after conflicts between friends. Friendly relationships can be described by three dimensions (i.e. value, security and compatibility); however, research into the relative importance of these dimensions for the occurrence of reconciliation is sparse. Moreover, reconciliation may depend on factors other than the social relationship between opponents including, for example, their social status or the context of the conflict. Our study aimed at analysing which factors are important determinants of reconciliation and at testing the valuable relationship hypothesis, by analysing the relative effects of relationship value, security and compatibility on the occurrence and timing of reconciliation. We collected data on two troops of wild Japanese macaques living on Yakushima Island, Japan, and selected the best predicting variables of reconciliation using linear mixed models. Our results show that reconciliation occurs more frequently, and earlier, after conflicts between opponents who exchange a higher percentage of grooming. Two additional variables related to relationship security and value were selected in the best models: frequency of aggression and of approaches resulting in tolerated co-feeding. Among the variables not related to relationship quality, distance between opponents at the end of the conflict, kinship, sex of the opponents and context of conflict (i.e. during feeding or social time) were included in our models. Our findings support the valuable relationship hypothesis and, in particular, highlight that the fitness-related benefits of social relationships (i.e. the relationship value) are important determinants of the evolution of friendly relationships and reconciliation.
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Clucas, B., Marzluff, J. M., Mackovjak, D., & Palmquist, I. (2013). Do American Crows Pay Attention to Human Gaze and Facial Expressions? Ethology, 119(4), 296–302.
Abstract: Interactions between species can lead to the evolution of interspecific communication. Non-verbal communication by humans, both intentional and unintentional, can be interpreted by other species. We tested whether American crows (Corvus brachyrhynchos) were sensitive to human facial features under field conditions by comparing flight initiation distances and urgency of escape behavior to human approaches varying in eye contact and facial expression. We first examined whether crows distinguish between an approaching human who is directly gazing at them and a human approaching them with an averted gaze. In a second experiment, we tested whether crows differentiate a smiling from scowling human approaching them with direct or averted gaze. In the first experiment, we found that crows fled sooner and more urgently when humans were directly gazing at them. Similarly, in the second experiment, crows responded sooner to a direct vs. averted gaze; however, they did not react differently to varying human facial expressions. We suggest that crows use human gaze as a reliable visual cue compared with facial expressions when making decisions about responding to approaching humans. This is the first study to show that a wild corvid species changes its behavior based on human gaze, possibly representing an adaptation to living in human-dominated urban areas and suggesting crows might perceive human intention by this visual cue.
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Seferta, A., Guay, P. - J., Marzinotto, E., & Lefebvre, L. (2001). Learning Differences between Feral Pigeons and Zenaida Doves: The Role of Neophobia and Human Proximity. Ethology, 107, 281–293.
Abstract: Learning differences predicted from ecological variables can be confounded with differences in wariness of novel stimuli (neophobia). Previous work on feral pigeons (Columba livia), as well as on group-feeding and territorial zenaida doves (Zenaida aurita), reported individual and social learning differences predicted from social foraging mode. In the present study, we show that speed of learning a foraging task covaries with neophobia and latency to feed from a familiar dish in the three types of columbids. Pigeons were much faster than either territorial or group-feeding zenaida doves on all tests conducted in captivity, but showed unexpectedly strong neophobia in some urban flocks during field tests. Human proximity strongly affected performance in group-feeding doves both in the field and in captivity. They were slightly faster at learning than their territorial conspecifics in cage tests. In multiple regressions, species identity, but not social foraging mode, significantly predicted individual variation in learning, as did individual variation in neophobia. Wariness of novel stimuli and species differences associated with artificial selection appear to be more important than foraging mode and wariness of humans in accounting for learning differences between these columbids.
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Dunbar, R. I. M., & Bever, J. (1998). Neocortex size predicts group size in carnivores and some insectivores. Ethology, 108(8), 695–708.
Abstract: Neocortex size has been shown to correlate with group size in primates. Data for carnivores and insectivores are used to test the generality of this relationship. The data suggest that carnivores lie on the same grade as the primates, but that insectivores lie on a separate grade to the left of these two orders. Among the insectivores, there appears to be a distinction between the 'advanced' genera (which show a relationship between group size and neocortex size) and the 'basal' genera (which do not).
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Fucikova, E., Drent, P. J., Smits, N., & van Oers, K. (2009). Handling Stress as a Measurement of Personality in Great Tit Nestlings (Parus major). Ethology, 115(4), 366–374.
Abstract: nterest in personality is growing in a wide range of disciplines, but only in a few systems it is possible to assess the survival value of personality. Field studies looking at the relationship between personality and survival value early in life are greatly hampered by the fact that personality can at present only be assessed after individuals become independent from their parents. In passerines, for example, this is often after a period of intensive selection for the survival on fledglings. The main aim of this study is therefore to develop a method to measure personality before this period of selection. For this purpose, we developed the handling stress (HS) test. We measured HS in 14-d-old great tit nestlings by counting the number of breast movements (breath rate) in four subsequent 15-s bouts for 1 min; before and after they were socially isolated from their siblings for 15 min. To calculate the repeatability of HS, we repeated the test 6 mo later. To assess the relationship between HS and exploratory behaviour, we correlated the outcome of both tests. We ran tests both on birds of lines selected for extreme personality and on wild birds from a natural population. We found that birds selected for fast exploration reacted more to HS compared with birds selected for slow exploration and that HS was repeatable in different life phases. We confirmed this by finding an increase in the HS with increasing exploratory scores in wild birds. These results show that we can use the HS test as a measurement of personality, making it a potential tool for studying the relationship between personality and survival value early in life.
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Majolo, B., Ventura, R., & Koyama, N. F. (2009). Anxiety Level Predicts Post-Conflict Behaviour in Wild Japanese Macaques (Macaca fuscata yakui) (Vol. 115). © 2009 Blackwell Verlag GmbH.
Abstract: Reconciliation (i.e. the post-conflict exchange of friendly behaviour between former opponents) functions to control for the detrimental effects that aggression may have on social relationships. Studies conducted so far have investigated intra-individual sources of variation in post-conflict behaviour, showing that animals have a stronger increase in anxiety and are more likely to reconcile after conflicts with valuable partners, such as kin. Much less attention has been given to how differences between individuals in emotional profiles affect post-conflict behaviour. Our aim was to analyse whether inter-individual differences in baseline anxiety levels predicted the magnitude of the increase in anxiety following a conflict and the occurrence of reconciliation. We collected data on two groups of wild Japanese macaques (Macaca fuscata yakui). Animals having a higher baseline level of anxiety had a more dramatic anxious response following a conflict while controlling for a series of factors (e.g. relationship quality between opponents). These more anxious animals were also less likely to reconcile than more relaxed individuals. Therefore, more anxious animals face some social costs by being less able to cope with the post-conflict condition. We propose that differences in anxiety levels may be interpreted as tradeoffs between benefits and costs across conditions. For example, more anxious animals, who are less able to reconcile conflicts, might also be less exploratory and thus face a lower risk to eat unknown, poisonous food.
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Giada Cordoni, & Elisabetta Palagi. (2008). Reconciliation in Wolves (Canis lupus) – New Evidence for a Comparative Perspective. Ethology, 114, 298–308.
Abstract: Social animals gain benefits from cooperative behaviours. However, social systems also imply competition and conflict of interest. To cope with dispersal forces, group-living animals use several peace-keeping tactics, which have been deeply investigated in primates. Other taxa, however, have been often neglected in this field research. Wolves (Canis lupus) with their high sociality and cooperative behaviour may be a good model species to investigate the reconciliation process. In this study, we provide the first evidence for the occurrence of reconciliation in a group of zoo-kept wolves. The conciliatory contacts were uniformly distributed across the different sex-class combinations. We found a linear dominance hierarchy in the colony under study, although the hierarchical relationships did not seem to affect the reconciliation dynamics. Moreover, both aggressors and victims initiated first post-conflict affinitive contact with comparable rates and both high- and low-intensity conflicts were reconciled with similar percentages. Finally, we found that coalitionary support may be a good predictor for high level of conciliatory contacts in this species.
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Blumstein, D. T., Barrow, L., & Luterra, M. (2008). Olfactory Predator Discrimination in Yellow-Bellied Marmots. Ethology, 114(11), 1135–1143.
Abstract: The mechanism underlying olfactory predator identification may be relatively experience-independent, or it may rely on specific experience with predators. A mechanism by which prey might identify novel predators relies on the inevitable creation of sulfurous metabolites that are then excreted in the urine of carnivorous mammals. We tested whether free-living, yellow-bellied marmots (Marmota flaviventris) and mid-sized herbivores that fall prey to a variety of carnivorous mammals could discriminate herbivore (elk-Cervus elephas) urine from predator (red fox-Vulpes vulpes, coyote-Canis latrans, mountain lion-Felis concolor, wolf-Canis lupus) urine, a novel herbivore (moose-Alces alces), and a distilled water control. We further asked how specific this assessment was by testing whether marmots responded differently to predators representing different levels of risk and to familiar vs. unfamiliar predators. We found that marmots responded more to urine from coyotes (a familiar predator on adults), mountain lions (a potentially unfamiliar predator that could kill adults) and wolves (a locally extinct predator that could kill adults) than to elk urine (a non-predator). Red fox (a predator that poses a risk only to recently emerged marmot pups) urine elicited a less substantial (but not significantly so) response than coyote urine. Marmots can identify predators, even novel ones, using olfactory cues, suggesting that experience with a specific predator is not required to identify potential threats.
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Amandine Ramseyer, Bernard Thierry, Alain Boissy, & Bertrand Dumont. (2009). Decision-making Processes in Group Departures of Cattle. Ethology, 115(10), 948–957.
Abstract: To keep social cohesiveness, group-living animals have to reach consensus decisions through recruitment processes. This implies that decision-making depends on the behaviours and social relationships of several group members at different stages of movements. We tested these assumptions in a group of fifteen 18-mo-old Charolais heifers (Bos taurus) at pasture, in which two observers continuously videotaped social interactions and group departures after resting periods. These departures were preceded by a phase of preparation characterized by an increase in activity. The number of heifers participating to a movement increased with the number of group members oriented in the direction of the movement before departure. The first moving animal also recruited a higher number of mates when it had a greater number of close neighbours, the first individuals to follow being mainly its preferential partners. Coercive interactions such as pressing behaviours were observed within the 5 min preceding or following departure. After departure, the numbers of walks and restarts of the first two movers were still operative in recruiting others. The frequency of pauses of the first mover was significantly higher when it was not followed, meaning that it adjusted its behaviour to that of other group members. Decision-making was distributed among group members, with any individual being liable to move first. The behaviour of cows and their spatial distribution before departure, at departure and after departure significantly affected the number of participants in the movement, demonstrating that decision-making was time-distributed in the studied cattle group.
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Briard, L., Dorn, C., & Petit, O. (2015). Personality and Affinities Play a Key Role in the Organisation of Collective Movements in a Group of Domestic Horses. Ethology, 121(9), 888–902.
Abstract: Understanding how groups of individuals with different motives come to daily decisions about the exploitation of their environment is a key question in animal behaviour. While interindividual differences are often seen only as a threat to group cohesion, growing evidence shows that they may to some extent facilitate effective collective action. Recent studies suggest that personality differences influence how individuals are attracted to conspecifics and affect their behaviour as an initiator or a follower. However, most of the existing studies are limited to a few taxa, mainly social fish and arthropods. Horses are social herbivores that live in long-lasting groups and show identifiable personality differences between individuals. We studied a group of 38 individuals living in a 30-ha hilly pasture. Over 200 h, we sought to identify how far individual differences such as personality and affinity distribution affect the dynamic of their collective movements. First, we report that individuals distribute their relationships according to similar personality and hierarchical rank. This is the first study that demonstrates a positive assortment between unrelated individuals according to personality in a mammal species. Second, we measured individual propensity to initiate and found that bold individuals initiated more often than shy individuals. However, their success in terms of number of followers and joining duration did not depend on their individual characteristics. Moreover, joining process is influenced by social network, with preferred partners following each other and bolder individuals being located more often at the front of the movement. Our results illustrate the importance of taking into account interindividual behavioural differences in studies of social behaviours.
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