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Palombit, R. A., Seyfarth, R. M., & Cheney, D. L. (1997). The adaptive value of 'friendships' to female baboons: experimental and observational evidence. Anim. Behav., 54(3), 599–614.
Abstract: Lactating female baboons, Papio cynocephalusoften maintain close associations with particular males. There are at least three proposed benefits of 'friendships' to females: (1) male protection against potentially infanticidal males; (2) male protection against harassment by dominant females; (3) male attachment to an infant that develops into future care of juveniles. These hypotheses were examined in a population of chacma baboons, P. c. ursinusin which male infanticide accounted for at least 38% of infant mortality. Almost all mothers of young infants formed strong bonds with one or two males with whom they had copulated during the cycle in which they conceived their infants. Females were primarily responsible for maintaining friendships during lactation, but they terminated these relationships if their infants died. In playbacks of females' screams, male friends responded more strongly than control males. They also responded more strongly to the screams of female friends than to the screams of control females. Following an infant's death, however, male friends responded less strongly than control males to the same females' screams. Finally, male friends responded more strongly than control males to playback sequences in which female screams were combined with the threat vocalizations of a potentially infanticidal alpha male, but not when female screams were combined with the threat calls of a non-infanticidal male or the alpha female. Both observations and experiments suggest that the benefits of friendships to females derive from the protection of their infants against infanticide.1997The Association for the Study of Animal Behaviour
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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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Castles, D. L., Whiten, A., & Aureli, F. (1999). Social anxiety, relationships and self-directed behaviour among wild female olive baboons. Anim. Behav., 58(6), 1207–1215.
Abstract: Self-directed behaviour (SDB) can be used as a behavioural indicator of stress and anxiety in nonhuman primates (Maestripieri et al. 1992, Animal Behaviour, 44, 967-979). We investigated the effect of nearest neighbours' relative dominance status on the SDB of sexually mature female olive baboons, Papio anubis. When the animal nearest to (within 5 m of) a female was a dominant individual, SDB rates (a combined measure of self-scratching, self-grooming, self-touching, body shaking and yawning) increased by ca. 40% over those observed when the nearest neighbour was a subordinate. The results indicate that (1) SDB can be used as a measure of uncertainty during the social interactions of cercopithecine primates and (2) as there was considerable variation in SDB response according to the nature of the dominant individual, SDB can be used to assess relationship security (i.e. the perceived predictability of a relationship for one partner). Finally, in combination with measures of affiliation rate, SDB may provide insight into relationship value.
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Eccles, T. R., & Shackleton, D. M. (1986). Correlates and consequences of social status in female bighorn sheep. Anim. Behav., 34(5), 1392–1401.
Abstract: Dominance-subordinance relationships among a captive group of adule bighorn sheep (Ovis canadensis californiana) were studied from May 1977 to December 1978. Social interactions between females were brief in duration and infrequent. Although a dominance hierarchy was evident among the females, it was not linear. Horn length and body weight were not consistently correlated with social status. The highest ranking females were the most aggressive individuals, initiating more agonistic interactions than subordinates. Females with high social status did not have higher quality diets, lower activity costs, or higher productivity than low ranking females.
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Fournier, F., & Festa-Bianchet, M. (1995). Social dominance in adult female mountain goats. Anim. Behav., 49(6), 1449–1459.
Abstract: The social behaviour of adult female mountain goats, Oreamnos americanus, was studied for 2 years in an unhunted population in west-central Alberta, Canada. Compared with other female ungulates, mountain goat females interacted aggressively much more frequently and their dominance ranks were less stable in time and less age-related. Goats were organized in a non-linear but non-random dominance hierarchy, with many reversals in rank. The best morphological predictor of dominance rank was horn length one year and body mass in the following year. Age was a weaker predictor of dominance status than what has been reported for other female ungulates. The ranks of individual goats changed between years and dominance rank one year was not a good predictor of rank the following year. These results suggest that linearity may only be possible when a contested resource can be defended. Dominant female goats did not forage more efficiently than subordinate goats, and dominant status did not affect the amount of time devoted to alert behaviour.
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Rutberg, A. T., & Greenberg, S. A. (1990). Dominance, aggression frequencies and modes of aggressive competition in feral pony mares. Anim. Behav., 40(2), 322–331.
Abstract: Feral pony mares, Equus caballus, at Assateague Island, Maryland, formed linear dominance hierarchies within bands. Generally, older mares dominated younger mares, and larger mares dominated smaller mares. Large mares initiated aggression more often than small mares when age was controlled for but, surprisingly, older mares initiated aggression less often than younger mares when size was controlled for. Thus, mares peak in aggressiveness fairly soon after achieving full size and then, while maintaining or improving their rank in the domainance hierarchy, progressively reduce their involvement in aggression as they grow older, Involvement in aggression per mare increased as number of mares in the group increased; this effect was independent of nearest-mare distances. Frequency of involvement in aggression did not differ between mares that had changed bands within the year and mares whose band association had continued for a year or more. Aggression was directed more frequently than expected at subordinate mares who were nursing, and also occurred more frequently than expected at water holes. The proportion of aggressive encounters during grazing closely matched the total proportion of time spent grazing. Subordinate mares with foals received aggression more often than subordinate mares without foals. The high frequency of aggression associated with foals and nursing suggests that interference with reproduction of subordiantes is an important mode of competition between mares. Such interference may be common in animals that feed on dispersed resources and live in small, cohesive groups.
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Clutton-Brock, T. H., & Parker, G. A. (1995). Sexual coercion in animal societies. Anim. Behav., 49(5), 1345–1365.
Abstract: In a wide range of animal species, males coerce females to mate with them, either by physically forcing them to mate, by harassing them until they mate or by punishing persistent refusal to mate. The first section of this paper argues that the possibility of forced copulation can generate arms races between males and females that may have substantial costs to both sexes. In the second section, it is suggested that sexual harassment commonly represents a `war of attrition' between the sexes; existing game theory models that may apply to sexual conflict over mating decisions are reviewed. The third section develops a simple prospective model for the evolution of intimidation by punishment in situations where males can raise the probability that females will accept their advances in future by punishing them for refusal to mate. Where the benefits of sexual coercion to males are high, all three male strategies may develop to a point where they have substantial costs to females. In the final section, evidence that female behaviour is adapted to minimizing these costs is reviewed.
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Duncan, P., & Vigne, N. (1979). The effect of group size in horses on the rate of attacks by blood-sucking flies. Anim. Behav., 27(Part 2), 623–625.
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Sayigh, L. S., Tyack, P. L., Wells, R. S., Solow, A. R., Scott, M. D., & Irvine, A. B. (1999). Individual recognition in wild bottlenose dolphins: a field test using playback experiments. Anim. Behav., 57(1), 41–50.
Abstract: We conducted playback experiments with wild bottlenose dolphins, Tursiops truncatus, to determine whether there is sufficient information in their individually distinctive signature whistles for individual recognition. We conducted experiments with members of a resident community of dolphins in waters near Sarasota, Florida, during temporary capture-release projects. We used a paired playback design, wherein the same two whistle sequences were predicted to evoke opposite responses from two different target animals. This design controlled for any unknown cues that may have been present in the playback stimuli. We predicted that mothers would respond more strongly to the whistles of their own independent offspring than to the whistles of a familiar, similar-aged nonoffspring. Similarly, we predicted that independent offspring would respond more strongly to the whistles of their own mother than to the whistles of a familiar, similar-aged female. Target animals were significantly (P<0.02) more likely to respond to the predicted stimuli, with responses measured by the number of head turns towards the playback speaker. In bottlenose dolphin societies, stable, individual-specific relationships are intermixed with fluid patterns of association between individuals. In primate species that live in similar 'fission-fusion' type societies, individual recognition is commonplace. Thus, when taken in the context of what is known about the social structure and behaviour of bottlenose dolphins, these playback experiments suggest that signature whistles are used for individual recognition. Copyright 1999 The Association for the Study of Animal Behaviour.
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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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