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Boinski, S. (2005). Dispersal patterns among three species of squirrel monkeys (Saimiri oerstedii, S. boliviensis and S. sciureus): III. Cognition. Behaviour, 142, 679–699.
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Conradt, L., & Roper, T. J. (2010). Deciding group movements: Where and when to go. Behav. Process., 84(3), 675–677.
Abstract: A group of animals can only move cohesively, if group members “somehow” reach a consensus about the timing (e.g., start) and the spatial direction/destination of the collective movement. Timing and spatial decisions usually differ with respect to the continuity of their cost/benefit distribution in such a way that, in principle, compromises are much more feasible in timing decision (e.g. median preferred time) than they are in spatial decisions. The consequence is that consensus costs connected to collective timing decisions are usually less skewed amongst group members than are consensus costs connected to spatial decisions. This, in turn, influences the evolution of decision sharing: sharing in timing decisions is most likely to evolve when conflicts are high relative to group cohesion benefits, while sharing in spatial decisions is most likely to evolve in the opposite situation. We discuss the implications of these differences for the study of collective movement decisions.
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Cameron, E. Z., Stafford, K. J., Linklater, W. L., & Veltman, C. J. (1999). Suckling behaviour does not measure milk intake in horses, Equus caballus. Anim. Behav., 57(3), 673–678.
Abstract: Studies of parental investment in mammals have frequently used suckling behaviour to estimate energy transfer from mother to offspring, and consequently to measure maternal input. Such studies assume that the more an offspring sucks, the more milk it will receive. This assumption has been questioned, and a review of the literature found little support for it. To test if suckling behaviour provided an accurate index of milk or energy intake we used a radioactive isotope technique to label the milk of thoroughbred mares and to measure milk transfer to foals. We found no significant linear relationship between usual measures of suckling behaviour and milk or energy intake. No behaviours associated with suckling nor with characteristics of mares and foals improved the relationship; only the number of butts associated with each suck episode even approached significance. If we had used suckling behaviour to test theories on differential maternal investment our conclusions would have been in error. For example, female foals tended to suck for longer than males did but there was no difference in the amount of milk transferred. Consequently, we show that measures of suckling behaviour do not adequately predict milk intake in the domestic horse and we suggest that conclusions about differential maternal investment in mammals based on suckling behaviour are likely to be in error. Copyright 1999 The Association for the Study of Animal Behaviour.
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Lonsdorf, E. V. (2005). Sex differences in the development of termite-fishing skills in the wild chimpanzees, Pan troglodytes schweinfurthii, of Gombe National Park, Tanzania. Anim. Behav., 70(3), 673–683.
Abstract: By the age of 5.5 years, all of the young chimpanzees of Gombe National Park have acquired a skill known as 'termite fishing'. Termite fishing involves inserting a flexible tool made from vegetation into a termite mound and extracting the termites that attack and cling to the tool. Although tool use is a well-known phenomenon in chimpanzees, little is known about how such skills develop in the wild. Prior studies have found adult sex differences in frequency, duration and efficiency of tool-using tasks, with females scoring higher on all measures. To investigate whether these sex differences occurred in youngsters, I performed a 4-year longitudinal field study during which I observed and videotaped young chimpanzees' development of the termite-fishing behaviour. Critical elements of the skill included identifying a hole, making a tool, inserting a tool into a hole and extracting termites. These elements appeared in the same order during the development of all subjects, but females typically peaked at least a year earlier than males in their performance of the skills that precede termite fishing. In addition, young females successfully termite-fished an average of 27 months earlier than young males and were more proficient at the skill after acquisition had occurred. Furthermore, the techniques of female offspring closely resembled those of their mothers whereas the techniques of male offspring did not, suggesting that the process by which termite fishing is learned differs for male and female chimpanzees.
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Wittemyer, G., & Getz, W. M. (2007). Hierarchical dominance structure and social organization in African elephants, Loxodonta africana. Anim. Behav., 73(4), 671–681.
Abstract: According to the socioecological framework, transitivity (or linearity) in dominance relationships is related to competition over critical resources. When a population is structured into groups, the intensity of between- versus within-group competition influences the form and function of its social organization. Few studies have compared the type and relative intensity of competition at these two levels. African elephants have well-structured social relations, providing an exemplary system for such a study. We report on dominance hierarchies among free-ranging elephants and evaluate the factors that drive their socioecological structure to lie in a region of the three-dimensional nepotism/despotism/tolerance space rarely observed among social species; namely, where non-nepotistic, transitive dominance hierarchies within groups emerge despite kin-based philopatry and infrequent agonistic interactions over widely distributed resources. We found significant transitivity in dominance hierarchies between groups. Dominance relations among the matriarchs of different social groups were primarily age based, rather than driven by physical or group size, and group matriarch rank influenced the dominance relationships among nonmatriarchal females in the population. Our results suggest that between-group dominance relationships induce tolerance among group members, which in combination with high group relatedness, reduces the benefits of nepotism. We postulate that cognitive abilities and high risk of injury in contests enhance winner and loser effects, facilitating the formation of transitive dominance relationships, despite widely distributed resources over which infrequent competition occurs. The interplay of cognitive abilities, winner and loser effects, resource distribution, and within- and between-group dominance relationships may produce behaviour in other strongly social mammals that differs from that predicted by a superficial application of current socioecological models.
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Griffin, A. S., & Galef, J., Bennett G. (2005). Social learning about predators: does timing matter? Anim. Behav., 69(3), 669–678.
Abstract: In Pavlovian conditioning, animals acquire a response to a previously neutral stimulus (conditioned stimulus, CS), such as a light, if that stimulus predicts a biologically important event (unconditioned stimulus, US), such as delivery of food. Learning typically occurs when the CS precedes the US (forward conditioning), and not when the CS follows the US (backward conditioning). In social learning about predators, the predator stimulus is considered to be the CS to which observers acquire avoidance responses after the stimulus has been presented in contiguity with an alarmed demonstrator, the US. We tested the prediction that social learning of response to a predator would occur even if the social alarm cues (the US) appeared before the predatory stimulus (the CS). Carib grackles, Quiscalus lugubris, responded to a familiar predator presented at close range by suppressing alarm calls. Presentation of an unfamiliar avian model (black-and-yellow pigeon) also decreased calling, and this inhibition of calling was enhanced following a training session in which the model stimulus was presented in association with grackle alarm calls. Acquired inhibition of calling was independent of the order of presentation of the model and an alarm chorus. These are the first results to indicate that social acquisition of predator avoidance is not dependent upon a particular temporal relationship between predators and social alarm cues. Evolution may have modified some properties of Pavlovian conditioning to accommodate social learning about potentially dangerous stimuli.
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Rands, S. A. (2010). Group-movement [`]initiation' and state-dependent decision-making. Behav. Process., 84(3), 668–670.
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Pillot, M. - H., & Deneubourg, J. - L. (2010). Collective movements, initiation and stops: Diversity of situations and law of parsimony. Behav. Process., 84(3), 657–661.
Abstract: The environment of animals is often heterogeneous, containing zones that may be dedicated specifically to resting, drinking or feeding. These functional zones may spread over a more or a less extensive area. Thus, mobile animals may have to move from one patch to another when resources are locally depleted or when they need to change activity. The mechanisms involved in collective movement appear simple at first glance, but a brief reflection shows the real difficulty of the problem in terms of the numerous environmental, physical, physiological and social parameters involved. This review is mainly concerned with collective movements, which are characterised by a directional and temporal coordination, where individuals mutually influence each other, meaning this coordination mainly depends on social interactions ([Huth and Wissel, 1992], [Warburton and Lazarus, 1991], [Couzin and Krause, 2003] and [Couzin et al., 2002]). In literature, two types of movement are discussed: large-scale movement and small-scale movement. First, we define these types of movement and then discuss the behavioural mechanisms involved. Secondly, we show that short and long movement but also moving and stopping may result from the outcome of parameters modulation underpinning collective decision-making.
Keywords: Collective movement; Decision-making; Sheep
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Boesch, C. (1994). Cooperative hunting in wild chimpanzees. Anim. Behav., 48(3), 653–667.
Abstract: A model for the evolution of cooperation shows that two conditions are necessary for cooperation to be stable: a hunting success rate that is low for single hunters and increases with group size, and a social mechanism limiting access to meat by non-hunters. Testing this model on TaI chimpanzees, Pan troglodytes, showed that (1) it pays for individuals to hunt in groups of three or four rather than alone or in pairs, and (2) cooperation is stable because hunters gain more at these group sizes than cheaters, owing to a meat-sharing pattern in which hunting, dominance and age, in that order, determine how much an individual gets. In addition, hunters provide cheaters (about 45% of the meat eaters) with the surplus they produce during the hunts. Thus, cooperation in Tai male chimpanzees is an evolutionarily stable strategy, and its success allows cheating to be an evolutionarily stable strategy for Tai female chimpanzees. In Gombe chimpanzees, cooperation is not stable, first, because hunting success is very high for single hunters, and second, because no social mechanism exists that limits access to meat by non-hunters. The analysis showed that some assumptions made when discussing cooperation in other social hunters might be wrong. This might downgrade our general perception of the importance of cooperation as an evolutionary cause of sociality.
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Judge, P. G., & De Waa, l F. B. M. (1997). Rhesus monkey behaviour under diverse population densities: coping with long-term crowding. Anim. Behav., 54(3), 643–662.
Abstract: A popular view is that high population density promotes behavioural pathology, particularly increased aggression. In contrast, according to a coping model, some primates have behavioural mechanisms (e.g. formal displays, reconciliation and grooming) that regulate social tensions and control the negative consequences of crowding. Seven captive rhesus monkey groups, Macaca mulattawere observed over a wide range of population densities where high-density groups were over 2000 times more crowded than low-density free-ranging groups. As density increased, male rhesus monkeys increased grooming and huddling but did not increase rates of aggression. Females increased all categories of behaviour examined (heavy aggression, mild aggression, formal bared-teeth displays, grooming and huddling), but the increases were not distributed uniformly to all classes of partners. Females increased only grooming, huddling and appeasement displays to males, increased only aggression and huddling with kin and increased all categories of behaviour to non-kin adult females. There were no differences in the percentage of aggressive conflicts reconciled across density conditions. Increased density had different effects on particular relationships. Relationships between females and males were characterized by a coping pattern in which animals modified their behaviour in ways that may decrease aggression under crowded conditions. Female relationships with kin and non-kin were characterized by increases in both aggression and friendly interactions as density increased. The different patterns of response to higher density may reflect different strategies depending on the strength and stability of relationships and the potential consequences if certain relationships are disrupted.1997The Association for the Study of Animal Behaviour
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