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Altmann, S. A., & Altmann, J. (2003). The transformation of behaviour field studies. Anim. Behav., 65(3), 413–423.
Abstract: As areas of science mature, they pass through three, broadly overlapping stages of development, characterized respectively by description, explanation and synthesis. Field research on animal behaviour is making the transition from an area with a preponderance of purely descriptive studies to one that also includes the development and testing of verifiable hypotheses about the structure, causes and consequences of behaviour. We survey several reasons for this transformation of behaviour field studies and some of the major trends that characterize it, including: (1) patterns discerned in our cumulative knowledge of natural history; (2) increased support for behaviour field studies; (3) interfaces with related areas of science; (4) the development of observational sampling methods and other aspects of data sampling and analysis; (5) the development of models of behaviour's adaptive functions and life-history consequences; (6) long-term field sites that make possible complete life histories, increased attention to individual differences and intergenerational studies of behaviour; and (7) the development of techniques for remote tracking of animals and for noninvasive, hands-off sampling of a range of behavioural, physiological, genetic and environmental phenomena. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.
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Leca, J. - B., Gunst, N., Thierry, B., & Petit, O. (2003). Distributed leadership in semifree-ranging white-faced capuchin monkeys. Anim. Behav., 66(6), 1045–1052.
Abstract: We investigated the initiation of group movements in white-faced capuchin monkeys, Cebus capucinus, with the aim of determining whether a single individual with high dominance status consistently leads movements or whether leadership is distributed between group members. The group studied was reared in semifree-ranging conditions. A multivariate analysis followed by univariate analyses demonstrated that leadership was not concentrated on a single individual in this species. All individuals could initiate a collective movement. Nearly half of group members regularly succeeded in recruiting at least three followers. Although both sexes had similar rates of start attempts, females succeeded more frequently than males. We found no significant effect of the dominance status on the percentage of successful attempts. The use of a slow speed, looking back towards the other group members, or trills by the initiator heightened the likelihood of success in group movement initiation. An initiator starting from a core position in a clumped group was more successful than one starting from an edge position in a clumped group or from a dispersed group. Furthermore, the probability of successful start attempts was higher when the group remained stationary for a long period. Leadership in white-faced capuchins appears to be distributed between group members rather than exclusively concentrated on high-ranking individuals. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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Reale, D., & Festa-Bianchet, M. (2003). Predator-induced natural selection on temperament in bighorn ewes. Anim. Behav., 65(3), 463–470.
Abstract: Temperament traits in animals may have important fitness consequences, but have received little attention from ecologists or evolutionary biologists. A few studies have linked variation in temperament with fitness, but none has measured selection on temperament traits. We estimated the strength of selection on female boldness and docility on bighorn sheep ewes, Ovis canadensis. The Ram Mountain population experienced little predation pressure during the first 25 years of study, then 2 years (1997 and 1998) of frequent predation by cougars, Puma concolor, during which adult ewe mortality almost tripled over the long-term average, to 27% a year. During years of high predation, we found moderate selection favouring bold ewes, and age-specific selection on docility. Old ewes appeared more vulnerable to predation than young ewes. In contrast, no evidence of selection on temperament traits was observed during 2 years of low predation (1996 and 1999). These results suggest predator-induced selection favouring bold and nondocile ewes. Leadership was highly correlated with age and may increase the risk of predator encounter. Leadership alone, however, could not explain the higher vulnerability of old ewes to predation. Cougar predation on bighorn sheep occurs sporadically and unpredictably, probably because individual cougars often are prey specialists. Cougar predation may have limited microevolutionary effects on temperament in bighorn sheep, because it mostly affects ewes near the end of their reproductive life span and because of potential countervailing selection on boldness and docility. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.
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Jennings, D. J., Gammell, M. P., Carlin, C. M., & Hayden, T. J. (2003). Is the parallel walk between competing male fallow deer, Dama dama, a lateral display of individual quality? Anim. Behav., 65(5), 1005–1012.
Abstract: During competitive encounters protagonists are expected to use signals of individual quality particularly if there is a risk of injury or death. Lateral presentation of body profile, by which information regarding phenotypic characteristics associated with individual quality are displayed, may represent such a strategy. During aggressive interactions, male fallow deer frequently engage in parallel walking which is assumed to represent a mutual display of quality, as mediated by exposure of the maximal profile of the body or antlers. We examined the context and role of the parallel walk during competitive encounters to investigate whether there was evidence that dyads of competing males were assessing differences in phenotypic characteristics. There was no evidence to support the hypotheses that the parallel walk is a lateral display of body size or weaponry or that its use is associated with a reduced level of escalated or risky behaviours during fighting. Total time spent fighting was not shorter when a parallel walk was present than when there was no parallel walk. The parallel walk was highly associated with fighting and it was more likely to be initiated by the subsequent loser. Furthermore, parallel walking frequently followed bouts of fighting and as such may represent a strategy that permits an animal the opportunity to decide whether to continue fighting. Parallel walking was also associated with a failure to resolve contests in favour of one animal indicating that it may be a means of withdrawing from further fighting without incurring a loss in dominance status. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.
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Miklósi, Á., Topál, J., & Csányi, V. (2004). Comparative social cognition: what can dogs teach us? Anim. Behav., 67(6), 995–1004.
Abstract: Research in comparative social cognition addresses how challenges of social living have formed the cognitive structures that control behaviours involved in communication, social learning and social understanding. In contrast to the traditional psychological approach, recent investigations take both evolutionary and functional questions into account, but the main emphasis is still on the mechanisms of behaviour. Although in traditional research `comparative' meant mainly comparisons between humans and other primates, ethological influences have led to a broadening of the spectrum of species under study. In this review, we evaluated how the study of dogs broadens our understanding of comparative social cognition. In the early days of ethology, dogs enjoyed considerable interest from ethologists, but during the last 20 years, dogs have rarely been studied by ethological methods. Through a complex evolutionary process, dogs became adapted for living in human society; therefore, the human environment and social setting now represents a natural ecological niche for this species. We have evidence that dogs have been selected for adaptations to human social life, and that these adaptations have led to marked changes in their communicative, social, cooperative and attachment behaviours towards humans. Until now, the study of dogs was hindered by the view that they represent an `artificial' species, but by accepting that dogs are adapted to their niche, as are other `natural' species, comparative investigations can be put into new light.
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Caro, T. M., Graham, C. M., Stoner, C. J., & Vargas, J. K. (2004). Adaptive significance of antipredator behaviour in artiodactyls. Anim. Behav., 67(2), 205–228.
Abstract: We used comparative data to test functional hypotheses for 17 antipredator behaviour patterns in artiodactyls. We examined the literature for hypotheses about auditory and visual signals, defensive behaviour and group-related antipredator behaviour in this taxon and derived a series of predictions for each hypothesis. Next, we documented occurrences of these behaviour patterns and morphological, ecological and behavioural variables for 200 species and coded them in binary format. We then pitted presence of an antipredator behaviour against presence of an independent variable for cervids, bovids and all artiodactyls together using nonparametric tests. Finally, we reanalysed the data using Maddison's (1990, Evolution, 44, 539-557) concentrated-changes tests and a consensus molecular and taxonomic phylogeny. We found evidence that snorting is both a warning signal to conspecifics and a pursuit-deterrent signal, lack of evidence that whistling alerts conspecifics and indications that foot stamping is a visual signal to warn group members. Evidence suggested that tail flagging was a signal to both conspecifics and predators, that bounding, leaping and stotting were used both as a signal and to clear obstacles and that prancing functioned similarly to foot stamping. Analyses of tail flicking, zigzagging and tacking were equivocal. We confirmed that inspection occurs in large groups, freezing enhances crypticity, and species seeking refuge in cliffs tend to be small. Entering water and attacks on predators had few correlates. Finally, group living, a putative antipredator adaptation, was associated with large body size and species living in open habitats, confirming Jarman's (1974, Behaviour, 48, 215-267) classic hypothesis. Bunching and group attack apparently deter predators. Despite limitations, comparative and systematic analyses can bolster adaptive hypotheses and raise new functional explanations for antipredator behaviour patterns in general.
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Hare, B., & Tomasello, M. (2004). Chimpanzees are more skilful in competitive than in cooperative cognitive tasks. Anim. Behav., 68(3), 571–581.
Abstract: In a series of four experiments, chimpanzees, Pan troglodytes, were given two cognitive tasks, an object choice task and a discrimination task (based on location), each in the context of either cooperation or competition. In both tasks chimpanzees performed more skilfully when competing than when cooperating, with some evidence that competition with conspecifics was especially facilitatory in the discrimination location task. This is the first study to demonstrate a facilitative cognitive effect for competition in a single experimental paradigm. We suggest that chimpanzee cognitive evolution is best understood in its socioecological context.
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Jennings, D. J., Gammell, M. P., Carlin, C. M., & Hayden, T. J. (2004). Effect of body weight, antler length, resource value and experience on fight duration and intensity in fallow deer. Anim. Behav., 68(1), 213–221.
Abstract: We tested predictions of evolutionary game theory focusing on fight duration and intensity during contests between European fallow deer, Dama dama L. We examined the relation between contest duration and intensity and resource-holding potential (RHP; body weight and antler size), in an effort to reveal the assessment rules used by competing males. We examined other potential determinants of duration and intensity: resource value (the oestrous female) and experience of agonistic interactions. Asymmetry in body weight or antler length of contestants was not correlated with fight duration. Body weight and antler length of the fight winner or loser were also not correlated with fight duration. Neither were the body weight of the heavier or lighter animal or the antler length of the animal that had longer or shorter antlers. A measure of intensity (the jump clash) was positively related to the body weight of the losing animal and the lighter member of the dyad. These results are consistent with the hypothesis that opponents escalate contest intensity based on assessment of their own ability rather than through mutual assessment. There was no evidence that resource value is an important factor in either fight duration or intensity in this population. As the number of fights between pairs of males increased, there was a decrease in fight duration. Fights were longer when at least one member of a competing pair of males had previously experienced a victory.
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Powell, F., & Banks, P. B. (2004). Do house mice modify their foraging behaviour in response to predator odours and habitat? Anim. Behav., 67(4), 753–759.
Abstract: Predator odours and habitat structure are thought to influence the behaviour of small mammalian prey, which use them as cues to reduce risks of predation. We tested this general hypothesis for house mice, Mus domesticus, by manipulating fox odour density via addition of fox scats and habitat via patchy mowing of vegetation, for populations in 15 x 15-m field enclosures. Using giving-up densities (GUDs), the density of food remaining when an animal quits harvesting a patch, we measured foraging behaviours in response to these treatments. Mice consistently avoided open areas, leaving GUDs two to four times greater in these areas than in densely vegetated patches. However, mouse GUDs did not change in response to the addition of fox scats, even immediately after fresh scats were added. There was no interaction between fox odour and habitat use. We then tested whether habituation to fox odours had occurred, by comparing the individual responses to scats of eight mice born into enclosures with fox scats to those of eight mice born into scat-free enclosures and five wild mice. In smaller enclosures, GUDs of trays with scats did not differ from GUDs of trays without scats for any treatment. We conclude that exposure to high levels of fox odours did not alter the foraging behaviour of mice, but that mice did reduce foraging in areas where habitat was removed, perceiving predation risk to be greater in these areas than controls. We suggest further that studies using the `scat-at-trap' technique, which have shown avoidance of predator odours by mice and other small mammals, may overestimate the general avoidance of predator odours by free-living prey, which must forage with a constant background of predator odours.
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Sands, J., & Creel, S. (2004). Social dominance, aggression and faecal glucocorticoid levels in a wild population of wolves, Canis lupus. Anim. Behav., 67(3), 387–396.
Abstract: Adrenal glucocorticoid (GC) secretion is an important component of the response to stress in vertebrates. A short-term increase in circulating GCs serves to redirect energy from processes that can be briefly curtailed without harm, allowing energy to be directed towards eliminating or avoiding the stressor. In contrast, prolonged elevation of GCs can cause a broad range of pathologies, including reproductive suppression. We examined whether social subordination in wolves leads to chronically elevated GC levels, and whether this [`]social stress' causes reproductive suppression of subordinates in cooperatively breeding species. Behavioural and endocrine data collected over 2 years from three packs of free-living wolves in Yellowstone National Park did not support this hypothesis. GC levels were significantly higher in dominant wolves than in subordinates, for both sexes, in all packs, in both years of study. Unlike other cooperatively breeding carnivores (e.g. dwarf mongooses, Helogale parvula, and African wild dogs, Lycaon pictus), high GCs in dominant wolves were not associated with high rates of aggression or agonistic interaction. Aggression increased for wolves of all ranks during mating periods, accompanied by a significant rise in GC levels. If chronic elevation of GCs carries fitness costs, then social stress in wolves (and many other social species) is a cost of dominance, not a consequence of subordination. The specific behavioural correlates of dominance that affect GC levels appear to vary among species, even those with similar social systems.
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