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Dunbar, R. I., & Dunbar, E. P. (1976). Contrasts in social structure among black-and-white colobus monkey groups. Anim. Behav., 24(1), 84–92.
Abstract: Three types of Colobus guereza groups may be distinguished on the bases of size and composition, namely small one-male groups, large, one-male groups and multi-male groups. The social structure of each type of group is described in terms of the distribution of non-agonistic interactions, the frequency and distribution of agonistic behaviour and the organization of the roles of vigilance, territorial defence and leadership. A number of differences are found between the group types which appear to be related to the differences in group size and composition. It is suggested that these group types represent stages in the life-cycle of colobus groups, and that such an interpretation may help to resolve some of the conflicting reports in the literature.
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Vervaecke, H., Stevens, J., Vandemoortele, H., Sigurjönsdöttir, H., & De Vries, H. (2007). Aggression and dominance in matched groups of subadult Icelandic horses (Equus caballus). J. Ethol., 25(3), 239–248.
Abstract: Abstract We studied sex differences in the nature of aggression and dominance behaviour in two newly formed groups of 1-year-old Icelandic horses. One herd contained nine geldings, the other nine mares. The groups were matched with regard to dominance-determining traits such as age, weaning age, composition of native herd, social experience, genetic origin, body condition and maternal dominance status. High-ranking individuals of both sexes were more aggressive, high-ranking males were older, and high-ranking females had a better body condition. Frequencies of aggressions were similar in both groups. The mares reacted significantly more by showing submission upon an aggression rather than by not responding or by escalating the aggression. For the geldings, this difference was not observed due to a lower tendency to submit. A linear dominance hierarchy was found in both groups. David`s scores provided additional information regarding cardinal rank distances and were used to calculate steepness of hierarchies. The female hierarchy was somewhat steeper compared to the male hierarchy, suggesting somewhat lower despotism among males. This was mainly a consequence of the lower unidirectionality in male submission. Male contests occurred predominantly between dyads at top and mid positions, suggesting a low degree of acceptance of the hierarchy.
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Mitman, G. (1990). Dominance, leadership, and aggression: animal behavior studies during the Second World War. J Hist Behav Sci, 26(1), 3–16.
Abstract: During the decade surrounding the Second World War, an extensive literature on the biological and psychological basis of aggression surfaced in America, a literature that in general emphasized the significance of learning and environment in the origins of aggressive behavior. Focusing on the animal behavior research of Warder Clyde Allee and John Paul Scott, this paper examines the complex interplay among conceptual, institutional, and societal forces that created and shaped a discourse on the subjects of aggression, dominance, and leadership within the context of World War II. The distinctions made between sexual and social dominance during this period, distinctions accentuated by the threat of totalitarianism abroad, and the varying ways that interpretations of behavior could be negotiated attests to the multiplicity of interactions that influence the development of scientific research.
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Anderson, J. R., Fornasieri, I., Ludes, E., & Roeder, J. - J. (1992). Social processes and innovative behaviour in changing groups of lemur fulvus. Behav. Process., 27(2), 101–112.
Abstract: A group of brown lemurs was presented with one or two baited food-boxes requiring a specific type of motor response in order to be opened. Subsequently, four groups containing different combinations of experienced individuals from the original group and naive individuals were tested. Solutions to the problem and access to the food were recorded and considered in relation to social factors. In the original group, two adult males learned to open the boxes, with one male increasingly preventing the other from approaching. In the second group, with the subordinate male and certain females removed, the dominant male tolerated successful performances by a juvenile female. Group 3 consisted of three passive female participants from the original group and a naive female; one of the three original females now became the sole box-opener. The introduction of the subordinate male from the original group into the all-female group led to a sharing of box-opening by this subject and the skilled female. In the final group, intense aggression toward the skilled female by a new, naive adult male resulted in two previously passive females succeeding on some occasions. In lemurs, at least some `scroungers' appear able to learn to perform a new act when the social context permits.
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Vallortigara, G., & Rogers, L. J. (2005). Survival with an asymmetrical brain: advantages and disadvantages of cerebral lateralization. Behav Brain Sci, 28(4), 575–89; discussion 589–633.
Abstract: Recent evidence in natural and semi-natural settings has revealed a variety of left-right perceptual asymmetries among vertebrates. These include preferential use of the left or right visual hemifield during activities such as searching for food, agonistic responses, or escape from predators in animals as different as fish, amphibians, reptiles, birds, and mammals. There are obvious disadvantages in showing such directional asymmetries because relevant stimuli may be located to the animal's left or right at random; there is no a priori association between the meaning of a stimulus (e.g., its being a predator or a food item) and its being located to the animal's left or right. Moreover, other organisms (e.g., predators) could exploit the predictability of behavior that arises from population-level lateral biases. It might be argued that lateralization of function enhances cognitive capacity and efficiency of the brain, thus counteracting the ecological disadvantages of lateral biases in behavior. However, such an increase in brain efficiency could be obtained by each individual being lateralized without any need to align the direction of the asymmetry in the majority of the individuals of the population. Here we argue that the alignment of the direction of behavioral asymmetries at the population level arises as an “evolutionarily stable strategy” under “social” pressures occurring when individually asymmetrical organisms must coordinate their behavior with the behavior of other asymmetrical organisms of the same or different species.
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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.
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Heitor, F., & Vicente, L. (2010). Affiliative relationships among Sorraia mares: influence of age, dominance, kinship and reproductive state. J. Ethol., 28(1), 133–140.
Abstract: Abstract Affiliative relationships among mares were examined in a managed group of Sorraia horses, Equus caballus, over a 3-year period. We assessed the influence of age, dominance, kinship and reproductive state on the strength of affiliative relationships and diversity of partners. The herd comprised 9–11 mares that had known each other since birth, their foals and a stallion that remained in the group exclusively during the breeding season. In contrast to a previous study, kinship did not significantly affect bonds. Mares tended to spend more time in proximity to those in the same reproductive state. Affiliative relationships among mares were relatively stable but their strength decreased after foaling, possibly as a function of foal protection and bonding between dam and foal. There was no consistent evidence that mares disengaged from affiliative relationships with increasing age. As expected, dominant mares and barren mares contributed the most to affiliative relationships. Dominance rank increased with age, but dominance relationships were stable and did not change after foaling. Overall, reproductive state was the factor that had the most consistent influence on affiliative relationships among Sorraia mares.
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Hemelrijk, C. K., & Wantia, J. (2005). Individual variation by self-organisation. Neurosci Biobehav Rev, 29(1), 125–136.
Abstract: In this paper, we show that differences in dominance and spatial centrality of individuals in a group may arise through self-organisation. Our instrument is a model, called DomWorld, that represents two traits that are often found in animals, namely grouping and competing. In this model individual differences grow under the following conditions: (1) when the intensity of aggression increases and grouping becomes denser, (2) when the degree of sexual dimorphism in fighting power increases. In this case the differences among females compared to males grow too, (3) when, upon encountering another individual, the tendency to attack is 'obligate' and not conditional, namely 'sensitive to risks'. Results resemble phenomena described for societies of primates, mice, birds and pigs.
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Brennan, J., & Anderson, J. (1988). Varying responses to feeding competition in a group of rhesus monkeys (Macaca mulatta). Primates, 29(3), 353–360.
Abstract: The behaviour of members of a group of rhesus monkeys was observed in experimentally created, competitive feeding situations. Socially dominant members of the group tended to start eating before lower-ranking subjects, and generally ate more. Dominants sometimes used aggression to control access to food, but overall, intermediate-ranking monkeys were involved in most agonistic episodes. Non-dominant subjects improved their feeding performance when food was presented in three piles rather than one pile, often by snatching food and consuming it away from the pile. These general patterns were less evident when realistic snake models were placed on some of the food piles. Feeding was disrupted by the presence of snakes, but notably, subordinates risked feeding in these conditions. Piles containing preferred foods and snakes were eaten from, but a low-preference food (carrot) under snakes went untouched by all subjects. The results suggest that group-members evaluate potential risks and benefits of competing for a restricted resource, and that dominance status, while an important factor, is only one element in the equation.
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Sueur, C., & Petit, O. (2008). Organization of Group Members at Departure Is Driven by Social Structure in Macaca. Int. J. Primatol., 29(4), 1085–1098.
Abstract: Abstract Researchers have often explained order of progression of group members during joint movement in terms of the influence of ecological pressures but rarely that of social constraints. We studied the order of joining by group members to a movement in semifree-ranging macaques with contrasting social systems: 1 group of Tonkean macaques (Macaca tonkeana) and 1 group of rhesus macaques (M. mulatta). We used network metrics to understand roles and associations among individuals. The way the macaques joined a movement reflected the social differences between the species in terms of dominance and kinship. Old and dominant male rhesus macaques were more often at the front of the movement, contrary to the Tonkean macaques, which exhibited no specific order. Moreover, rhesus macaques preferred to join high-ranking or related individuals, whereas Tonkean macaques based associations during joining mostly on sexual relationships with a subgroup of peripheral males.
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