|
|
Bourjade, M., Thierry, B., Maumy, M., & Petit, O. (2009). Decision-making in Przewalski horses (Equus ferus przewalskii) is driven by the ecological contexts of collective movements. Ethology, 115(4), 321–330.
Abstract: We addressed decision-making processes in the collective movements of
two groups of Przewalski horses (Equus ferus przewalskii) living in a semi
free-ranging population. We investigated whether different patterns of
group movement are related to certain ecological contexts (habitat use
and group activity) and analysed the possible decision-making processes
involved. We found two distinct patterns; ‘single-bout’ and ‘multiplebout’
movements occurred in both study groups. The movements were
defined by the occurrence of collective stops between bouts and differed
by their duration, distance covered and ecological context. For both
movements, we found that a preliminary period involving several horses
occurred before departure. In single-bout movements, all group members
rapidly joined the first moving horse, independently of the preliminary
period. In multiple-bout movements, however, the joining
process was longer; in particular when the number of decision-makers
and their pre-departure behaviour before departure increased. Multiplebout
movements were more often used by horses to switch habitats and
activities. This observation demonstrates that the horses need more time
to resolve motivational conflicts before these departures. We conclude
that decision-making in Przewalski horses is based on a shared consensus
process driven by ecological determinants.
|
|
|
|
Fraser, N. O., Schino, G., & Aureli, F. F. (2008). Components of Relationship Quality in Chimpanzees. Ethology, 114(9), 834–843.
Abstract: A novel approach to studying social relationships in captive adult chimpanzees (Pan troglodytes) was taken by using principal components analysis (PCA) to extract three key components of relationship quality from nine behavioural variables. Based on the loadings of the behavioural variables, the components appeared to match previously hypothesized critical aspects of social relationships and were therefore labelled Value, Compatibility and Security. The effects of kinship, sex combination, age difference and time spent together on each of the relationship quality components were analysed. As expected, kin were found to have more valuable, compatible and secure relationships than non-kin. Female2013female dyads were found to be more compatible than male2013male or mixed-sex dyads, whereas the latter were found to be most secure. Partners of a similar age were found to have more secure and more valuable relationships than those with a larger age gap. Individuals that were together in the group for longer were more valuable and more compatible, but their relationships were found to be less secure than individuals that were together in the group for a shorter time. Although some of the results may be unexpected based on chimpanzee socio-ecology, they fit well overall with the history and social dynamics of the study group. The methods used confer a significant advantage in producing quantitative composite measures of each component of relationship quality, obtained in an objective manner. These findings therefore promote the use of such measures in future studies requiring an assessment of the qualities of dyadic social relationships.
|
|
|
|
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.
|
|
|
|
Fedurek, P., & Dunbar, R. I. M. (2009). What Does Mutual Grooming Tell Us About Why Chimpanzees Groom? Ethology, 115(6), 566–575.
Abstract: Grooming might be a resource that is offered in exchange for some benefit (e.g. access to a feeding site or coalitionary support) or it might be a mechanism for building and servicing social relationships, whose function, in turn, is to facilitate the exchange of resources and services. Bi-directional (or simultaneous mutual) grooming is unusually common among chimpanzees (though rare in other primates) and we suggest that this might be because it is an especially strong indicator of social bonding. Because the bonding role of bi-directional grooming offers substantially different predictions from the interpretation offered by the models based on reciprocal altruism (RA), we use a critical tests methodology (i.e. tests that unequivocally support one hypothesis at the expense of the other) to differentiate between the bonding and RA hypotheses. We use data on the dynamics of grooming interactions from a captive group of chimpanzees (Pan troglodytes) to show that dominant individuals tolerated the individuals with whom they performed bi-directional grooming more than they did those who typically provided them unidirectional grooming. Dominants rejected and terminated grooming sessions more often with the individuals who provided them with mostly unidirectional grooming than with those with whom they groomed bi-directionally. In addition, animals engaged in bi-directional grooming more often with both relatives and those with whom they were often in proximity. These results support the bonding model of mutually reciprocated grooming at the expense of the RA model, and suggest that, at least in chimpanzees, simultaneous mutual grooming may play a particularly important role in social bonding.
|
|
|
|
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.
|
|
|
|
Raquel Monclús, & Heiko G. Rödel. (2009). Influence of Different Individual Traits on Vigilance Behaviour in European Rabbits. Ethology, 115(8), 758–766.
Abstract: An animal's level of vigilance depends on various environmental factors such as predator presence or the proximity of conspecific competitors. In addition, several individual traits may influence vigilance. We investigated the effects of body condition, social rank and the state of pregnancy on individual vigilance (scanning) rates in individually marked European rabbits (Oryctolagus cuniculus) of a field enclosure population. We found lower rates in young rabbits than in adult females, but male and female juveniles did not differ. Vigilance of juveniles was positively correlated with their age-dependent body mass (used as a measure of body condition), i.e. young rabbits with lower body condition scanned less. We suggest that juveniles with low body condition were trading off vigilance against feeding to maximise their growth. In contrast, there was no significant correlation between body mass and vigilance in adult females. Adult females increased scanning rates during late pregnancy, which might constitute a behavioural compensation because of their lower capacity to escape predator attacks. In addition, adult females with low social ranks scanned more than high ranking individuals, likely because of their higher risk of attacks by conspecifics. In summary, our results highlight various individual characteristics that influence vigilance behaviour in European rabbits.
|
|
|
|
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.
|
|
|
|
Wolff, A., & Hausberger, M. (1994). Behaviour of foals before weaning may have some genetic basis. Ethology, 96(1), 1–10.
Abstract: In this preliminary study on foal behaviour, 13 French saddlebred foals (2-3 mo old) and their dams were observed on pasture. The most important findings are the interindividual quantitative differences in foal behaviour patterns as well as in the amount of mainly foal-initiated time spent at given distances from their mares. Interindividual differences seem in part due to a sire effect
|
|
|
|
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.
|
|
|
|
Heitor, F., & Vicente, L. (2010). Dominance relationships and patterns of aggression in a bachelor group of Sorraia horses (Equus caballus). J. Ethol., 28(1), 35–44.
Abstract: Abstract The influence of individual factors on dominance rank and the relationship between rank distance and patterns of aggression predicted by models of evolutionarily stable strategies (ESS) of animal conflict were investigated in a managed bachelor group of Sorraia horses, Equus caballus. The group was composed of four to six stallions 3- to 12-years-old during the study period. The dominance hierarchy was significantly linear and rank was not related to age, weight, height or aggressiveness. Frequency and intensity of agonistic interactions were low, but higher-ranking stallions did not receive lower aggressiveness than lower-ranking stallions. There was some evidence that dominance relationships were more contested among close-ranking stallions, as predicted. Agonistic-related interactions among close-ranking stallions served similar functions to those among distant-ranking stallions, but the latter interacted more frequently than expected for access to resting sites and/or resting partners. Therefore, we found some evidence that agonistic-related interactions among distant-ranking stallions play a larger role in providing access to valuable and defendable resources than those among close-ranking stallions. Nevertheless, the fact that space to escape from aggression was limited and breeding access was independent from dominance rank may have reduced the benefits relative to costs of aggression and therefore limited the occurrence of contests over dominance and resources.
|
|
