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Heyes, C. M. (1995). Imitation and flattery: a reply to Byrne & Tomasello. Anim. Behav., 50(5), 1421–1424.
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Nicol, C. J., & Pope, S. J. (1999). The effects of demonstrator social status and prior foraging success on social learning in laying hens. Anim. Behav., 57(1), 163–171.
Abstract: Opportunities for social learning within a group of animals are likely to be influenced by the social dynamics of that group. Some individuals may be more influential demonstrators than others even when there are no differences in their skill level or performance. In this study of domestic hens,Gallus gallus domesticus, differences in demonstrator salience were examined. From 24 separate flocks we selected as demonstrators a dominant cockerel, a dominant hen, a mid-ranking hen or a subordinate hen. Demonstrators were pretrained to perform an operant discrimination task to obtain food. Six observers from each flock individually watched the demonstrator perform the task for four 5-min sessions held on consecutive days. On the fifth day observers were tested individually in the operant chamber. We analysed data from 19 flocks, where there were no quantitative differences in demonstrator performance. Observer hens of relatively high social status performed more correct operant pecks than observer hens of relatively low social status. Demonstrator category also had a significant effect on subsequent observer behaviour. Hens that had observed cockerels performed very few general pecks or operant pecks. Hens that had observed dominant hens performed more operant pecks, but hens that had observed sub-ordinate hens performed more general pecks in the chamber. The results suggested either that there was an interaction between dominance and gender in demonstrator salience or that dominant hens might have been influential because of some factor imperfectly associated with their dominance status. A possible candidate was the foraging ability of the dominant hens. In a second experiment using the same protocol, we manipulated the prior foraging success of dominant hens from four additional flocks but this had no significant effect on their subsequent influence as demonstrators.
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Janson, C. H. (1990). Social correlates of individual spatial choice in foraging groups of brown capuchin monkeys, Cebus apella. Anim. Behav., 40(5), 910–921.
Abstract: Individuals in a foraging group of wild bronwn capuchin monkeys choose different spatial positions relative to the rest of the group. Markov analysis of sequencess of individual spatial positions demonstrated significant differnces between individuals, which coul be categorized a posteriori into four homogenous subgroups. An individual's spatial position was related primarily to the amount of aggression it received from the group's dominant male, but also varied with its sex. Spatial choice varied with changes in an individual's social status, but did not vary consistently with seasonal differences in food availability. These results support the hypothesis that individuals compete for preferred spatial positions within a foraging group.
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Janson, C. H. (1990). Ecological consequences of individual spatial choice in foraging groups of brown capuchin monkeys, Cebus apella. Anim. Behav., 40(5), 922–934.
Abstract: Individuals in a foraging group of brown capuchin monkeys choose different spatial positions relative to the rest of the group. An individual's choice of spatial positiion affects its foraging success and perceived predation risk (as measured by vigilance behaviour). The two most dominant group members preferred to forage where their expected forwaging success was greatest. Juveniles chose to forage where their perceived predation risk was least, not where they would achieve the highest foraging success. The positions used by non-dominant adults neither maximized foraging success nor minimized predation risk. It is likely that subordinate adults accept spatial positions with suboptimal ecological consequences to avoid the costs of frequent confrontations with the dominant members of the group over foraging sites in poreferred positions.
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Crockford, C., Wittig, R. M., Seyfarth, R. M., & Cheney, D. L. (2007). Baboons eavesdrop to deduce mating opportunities. Anim. Behav., 73(5), 885–890.
Abstract: Many animals appear to monitor changes in other individuals' dominance ranks and social relationships and to track changes in them. However, it is not known whether they also track changes in very transient relationships. Rapid recognition of a temporary separation between a dominant male and a sexually receptive female, for example, should be adaptive in species where subordinate males use opportunistic strategies to achieve mating success. Dominant male baboons (Papio hamadryas ursinus) form sexual consortships with oestrous females that are characterized by mate guarding and close proximity. To assess whether subordinate males track temporary changes in the status of other males' consortships, we conducted playback experiments using a two-speaker paradigm. In the test condition, subjects heard the consort male's grunts played from one speaker and his consort female's copulation call played from a speaker approximately 40 m away. This sequence suggested that the male and female had temporarily separated and that the female was mating with another male. In a control trial, subjects heard another dominant male's grunts played from one speaker and the female's copulation call played from the other. In a second control trial, conducted within 24 h after the consortship had ended, subjects again heard the consort male's grunt and the female's copulation call played from separate speakers. As predicted, subjects responded strongly only in the test condition. Eavesdropping upon the temporal and spatial juxtaposition of other individuals' vocalizations may be one strategy by which male baboons achieve sneaky matings.
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Albers, P. C. H., & de Vries, H. (2001). Elo-rating as a tool in the sequential estimation of dominance strengths. Anim. Behav., 61(2), 489–495.
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Drummond, H., & Canales, C. (1998). Dominance between booby nestlings involves winner and loser effects. Anim. Behav., 55(6), 1669–1676.
Abstract: Two-chick broods of the blue-footed booby,Sula nebouxii, ordinarily exhibit stable dominance-subordinance, with the senior (first-hatched) chick habitually aggressive and the junior one habitually submissive (Nelson 1978,The Sulidae: Gannets and Boobies. London: Oxford University Press). But are both the subordinate and the dominant chick affected in their agonistic tendencies by early social experience? To answer this, we permanently paired subordinate and dominant chicks, 2-3 weeks old, with singletons (chicks lacking experience with a nestmate) by cross-fostering. During the first 4 h after pairing, subordinate chicks were seven times less aggressive than singletons and twice as likely to be submissive; dominant chicks were six times as aggressive as singletons. Although most subordinates consistently lost agonistic encounters during the first 10 days after pairing, the proportion of dominants that won decreased progressively until, by day 6, only about half of dominant chicks were winning. Early social experience has a strong but reversable training effect on both subordinates and dominants. Training as a subordinate showed more persistent effects than training as a dominant, possibly in part because our testing situation perpetuated subordinate training and counteracted dominant training.
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Hemelrijk, C. K. (2000). Towards the integration of social dominance and spatial structure. Anim. Behav., 59(5), 1035–1048.
Abstract: My aim was to show how individual-oriented (or artificial life) models may provide an integrative background for the development of theories about dominance by including effects of spatial structure. Dominance interactions are thought to serve two different, contrasting functions: acquisition of high rank and reduction of aggression. The model I present consists of a homogeneous virtual world inhabited by artificial agents whose actions are restricted to grouping and dominance interactions in which the effects of winning and losing are self-reinforcing. The two functions are implemented as strategies to initiate dominance interactions and the intensity of aggression and dominance perception (direct or memory based) are varied experimentally. Behaviour is studied by recording the same behavioural units as in real animals. Ranks appear to differentiate more clearly at high than at low intensity of aggression and also more in the case of direct than of memory-based rank perception. Strong differentiation of rank produces a cascade of unexpected effects that differ depending on which function is implemented: for instance, a decline in aggression, spatial centrality of dominants and a correlation between rank and aggression. Insight into the origination of these self-organized patterns leads to new hypotheses for the study of the social behaviour of real animals.
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Karavanich, C., & Atema, J. (1998). Individual recognition and memory in lobster dominance. Anim. Behav., 56(6), 1553–1560.
Abstract: American lobsters,Homarus americanus, form stable dominance relationships in captivity. Size, sex and stage in the moult cycle are important determinants for dominance. Other factors, such as recent agonistic experience play a role. This paper investigates how lobsters maintain their stable dominance relationships: they may recognize individuals or alternatively, recognize overall dominance status. We paired lobsters in two consecutive `boxing matches'. Results indicate that lobsters remember familiar opponents when kept either in isolation or in communal tanks for 24 h between their first and second fights. Subordinates immediately backed away from familiar dominants, avoiding a second fight. In some animals, this memory lasted between 1-2 weeks if pairs were kept separate between the first and second fights. When paired for the second fight against unfamiliar dominant lobsters, subordinate lobsters from first fights actively fought and won the encounter. These results suggest that lobsters are capable of `individual recognition'. In nature, the observed social organization of lobsters may be maintained by individual recognition of a small number of residents inhabiting separate, nearby shelters.
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Thouless, C. R., & Guinness, F. E. (1986). Conflict between red deer hinds: the winner always wins. Anim. Behav., 34(4), 1166–1171.
Abstract: Dominance relations between free-living, female red deer (hinds) (Cervus elaphus L.) on the Isle of Rhum, Scotland, were investigated. Most interactions were won by the older hind of the pair and this was the case even when both individuals had reached full body size. The younger hind was more likely to be the winner if the conflict was escalated or if the two hinds were strangers, in which case escalation was more frequent than usual. When outside their normal home range, older hinds were much more likely to lose, and younger ones more likely to win, than usual. These results can be best explained by the hinds using previous experience as a cue for conventional resolution of conflict, with the result that dominance relationships established early in life are perpetuated. No such cue is available if the hinds have not previously met.
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