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Nagy, M., Akos, Z., Biro, D., & Vicsek, T. (2010). Hierarchical group dynamics in pigeon flocks. Nature, 464(7290), 890–893.
Abstract: Animals that travel together in groups display a variety of fascinating motion patterns thought to be the result of delicate local interactions among group members1, 2, 3. Although the most informative way of investigating and interpreting collective movement phenomena would be afforded by the collection of high-resolution spatiotemporal data from moving individuals, such data are scarce4, 5, 6, 7 and are virtually non-existent for long-distance group motion within a natural setting because of the associated technological difficulties8. Here we present results of experiments in which track logs of homing pigeons flying in flocks of up to 10 individuals have been obtained by high-resolution lightweight GPS devices and analysed using a variety of correlation functions inspired by approaches common in statistical physics. We find a well-defined hierarchy among flock members from data concerning leading roles in pairwise interactions, defined on the basis of characteristic delay times between birds’ directional choices. The average spatial position of a pigeon within the flock strongly correlates with its place in the hierarchy, and birds respond more quickly to conspecifics perceived primarily through the left eye—both results revealing differential roles for birds that assume different positions with respect to flock-mates. From an evolutionary perspective, our results suggest that hierarchical organization of group flight may be more efficient than an egalitarian one, at least for those flock sizes that permit regular pairwise interactions among group members, during which leader–follower relationships are consistently manifested.
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Nagy, K., Bodó, G., Bárdos, G., Bánszky, N., & Kabai, P. (2010). Differences in temperament traits between crib-biting and control horses. Appl. Anim. Behav. Sci., 122(1), 41–47.
Abstract: Recent studies have suggested that crib-biting in horses is associated with diminished capacity of learning or coping with stress. Such findings raise the question whether trainability, which is fundamentally important in practice, could also be affected by stereotypic behaviour. Trainability of a horse is difficult to assess in simple tests, however, it is reliably estimated by experienced riders. To assess trainability and other characteristics related to that, a questionnaire survey was conducted with the owners of 50 crib-biting and 50 control horses. Where possible, control horses were selected from the same establishment as crib-biters. Groups did not differ significantly regarding age, breed, gender, training level or usage. Principal component analysis revealed three main factors which can be labelled as [`]Anxiety', [`]Affability' and [`]Trainability'. The [`]Anxiety' factor consisted of the items [`]Nervousness', [`]Excitability', [`]Panic', [`]Inconsistent emotionality', [`]Vigilance', [`]Skittishness', and [`]Timidity'. [`]Affability' consisted of [`]Friendliness toward people', [`]Cooperation', [`]Docility' and [`]Friendliness toward horses'. [`]Trainability' involved [`]Concentration', [`]Trainability', [`]Memory', and [`]Perseverance'. Temperament traits were not affected by age, gender, breed or training level, but the usage of the horse and the presence of crib-biting behaviour had significant effects. Competition horses had lower level of [`]Anxiety' (p = 0.032) and higher level of [`]Trainability' (p = 0.068) than leisure horses. Crib-biting horses had significantly lower level of [`]Anxiety' than control horses (p < 0.001), while [`]Trainability' and [`]Affability' did not differ between groups (p = 0.823 and p = 0.543, respectively). Competition horses are more often exposed to novel environment and to frightening stimuli (e.g. colourful obstacles) than leisure horses and therefore might have also become more habituated to these types of stimuli. Coping with novel situation may be enhanced by defusing nervous behaviour by the more experienced riders of competition. Previous studies indicated crib-biting horses to be less reactive when challenged as compared to control horses. We suggest that the virtual calmness and lower nervousness of the crib-biting horses might be due to the passive coping style of these animals. [`]Affability' of horses might be more related to housing and management conditions than to crib-biting. Contrary to expectations, scores on [`]Trainability' had not coincided with the impaired learning of crib-biting horses reported in laboratory tests. However, previous behavioural tests on equine learning rarely had a direct relevance to the training abilities of the horses. Our results do not support crib-biting stereotypy to affect performance in training, which is a complex learning process involving cooperation and docility in the social environment.
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McPhee, M. E., Segal, A., & Johnston, R. E. (2010). Hamsters Use Predator Odors as Indirect Cues of Predation Risk. Ethology, 116(6), 517–523.
Abstract: Abstract Golden hamsters (Mesocricetus auratus) use olfactory cues to assess traits of conspecifics such as kinship, individual identity, and reproductive status. The environment, however, is full of a wide variety of other olfactory information such as signals emitted by some of the hamster’s primary predators. Given this, we hypothesized that hamsters use odors from predators as an indirect sign of increased predation risk in the environment. In addition, based on data that show that wild hamsters are diurnal while laboratory hamsters are nocturnal, we hypothesized that if golden hamsters did respond to the predator odors, perceived predator risk might influence daily activity patterns in hamsters. We tested male and female hamsters over 5 d with scent gland secretion from domestic ferrets (Mustela putorius furo) and compared their behavior to that observed when they were exposed to a clean arena. In response to the predator odor, subjects significantly decreased the amount of time active outside of their burrow, returned to their burrow more quickly, and spent less time near the predator odor than the clean control stimulus. These results strongly support our hypothesis that hamsters, like other species of small mammals, avoid predator odors. The results did not, however, support our second hypothesis that exposure to predator odors during the dark phase of the light cycle would elicit a switch to a more diurnal pattern of activity. More work is needed to understand how environmental cues and internal mechanisms interact to shape activity patterns.
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McGreevy, P. D., Harman, A., McLean, A., & Hawson, L. (2010). Over-flexing the horse's neck: A modern equestrian obsession? Journal of Veterinary Behavior: Clinical Applications and Research, 5(4), 180–186.
Abstract: We used an opportunistic review of photographs of different adult and juvenile horses walking, trotting, and cantering (n = 828) to compare the angle of the nasal plane relative to vertical in feral and domestic horses at liberty (n = 450) with ridden horses advertised in a popular Australian horse magazine (n = 378). We assumed that horses in advertisements were shown at, what was perceived by the vendors to be, their best. Of the ridden horses, 68% had their nasal plane behind the vertical. The mean angle of the unridden horses at walk, trot, and canter (30.7 ± 11.5; 27.3 ± 12.0; 25.5 ± 11.0) was significantly greater than those of the ridden horses (1.4 ± 14.1; ?5.1 ± ?11.1; 3.1 ± 15.4, P < 0.001). Surprisingly, unridden domestic horses showed greater angles than feral horses or domestic horses at liberty. We compared adult and juvenile horses in all 3 gaits and found no significant difference. Taken together, these findings demonstrate that the longitudinal neck flexion of the degree desirable by popular opinion in ridden horses is not a common feature of unridden horses moving naturally. Moreover, they suggest that advertised horses in our series are generally being ridden at odds with their natural carriage and contrary to the international rules of dressage (as published by the International Equestrian Federation). These findings are discussed against the backdrop of the established doctrine, which states that carrying a rider necessitates changes in longitudinal flexion, and in the context of the current debate around hyperflexion.
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McCall, C. A., Hall, S., McElhenney, W. H., & Cummins, K. A. (2010). EVALUATION AND COMPARISON OF FOUR REACTIVITY TESTS IN HORSES. In Proc.17th Equine Nutr. Physiol. Symp (357). Lexington, KY.
Abstract: Four methods of ranking horses on reactivity were evaluated and compared: isolation from conspecifics, presentation of a static novel stimulus, traversing a novel stimulus in a runway (isolation, novel stimulus and runways tests, respectively) and assigning subjective emotionality scores. Forty horses performed each of the three tests daily on three different days in a switchback design where treatments were injection of a tranquilizer or vehicle. Horses were randomly assigned a daily test sequence, which was maintained throughout the study. In all tests, heart rates were recorded and behavior was videotaped. To be considered a valid test of reactivity, at least one heart rate and one behavioural measurement in the test had to show a significant difference due to tranquilization, and behavioural measures had to be displayed in at least 75% of the trials. In the runway test, no significant difference in heart rate values in tranquilized and non-tranquilized horses was found, and no behavioural attribute was displayed in more than 52% of the trials; therefore it was rejected as a valid test of reactivity. Both isolation and novel stimulus tests produced valid measurements. Mean heart rate was the most precise physiological measure for these tests, and walking and defecation frequency were the most precise behavioural measures for novel stimulus and isolation tests, respectively. Mean heart rates on the novel stimulus and isolation tests were correlated (rs=0.79, P<0.01) indicating that these tests produced similar rankings based on physiological responses. However, behavioural measures ranked horses differently (rs=0.27, P<0.10) on the tests. Rank correlations between mean heart rates and behavioural measures were higher in the novel stimulus (rs = 0.66, P<0.01) than the isolation test (rs = 0.55, P<0.01), indicating that the novel stimulus test ranked horses based on either physiological or behavioural responses more similarly than did the isolation test. Therefore, the novel stimulus test was considered the more accurate evaluation of reactivity. Subjective emotionality scores were correlated moderately with mean heart rates (rs > 0.33, P<0.01) from the novel stimulus and isolation tests and with walking scores (rs = 0.47, P<0.01) from the novel stimulus test. Assignment of subjective emotionality scores was not as accurate as the novel stimulus or isolation tests in ranking horses for reactivity. Using physiological data alone, combining physiological and behavioural measurements or using more than one behavioural measurement in reactivity tests may reflect the reactivity of the horse better than a single behavioural measurement.
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Massen, J., Sterck, E., & de Vos, H. (2010). Close social associations in animals and humans: functions and mechanisms of friendship (Vol. 147).
Abstract: Both humans and group-living animals associate and behave affiliatively more with some individuals than others. Human friendship has long been acknowledged, and recently scientists studying animal behaviour have started using the term friendship for close social associates in animals. Yet, while biologists describe friends as social tools to enhance fitness, social scientists describe human friendship as unconditional. We investigate whether these different descriptions reflect true differences in human friendship and animal close social associations or are a by-product of different research approaches: namely social scientists focussing on proximate and biologists on ultimate explanations. We first stress the importance of similar measures to determine close social associations, thereafter examine their ultimate benefits and proximate motivations, and discuss the latest findings on the central-neural regulation of social bonds. We conclude that both human friendship and animal close social associations are ultimately beneficial. On the proximate level, motivations for friendship in humans and for close social associations in animals are not necessarily based on benefits and are often unconditional. Moreover, humans share with many animals a similar physiological basis of sociality. Therefore, biologists and social scientist describe the same phenomenon, and the use of the term friendship for animals seems justified.
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Martín, J., López, P., Bonati, B., & Csermely, D. (2010). Lateralization When Monitoring Predators in the Wild: A Left Eye Control in the Common Wall Lizard (Podarcis muralis). Ethology, , no-no.
Abstract: Abstract Lateralization is the function specialization between left and right brain hemispheres. It is now ascertained in ectotherms too, where bias in eye use for different tasks, i.e., visual lateralization, is widespread. The lateral eye position on the head of ectotherm animals, in fact, allows them to observe left/right stimuli independently and allows lateralized individuals to carry out left and right perceived tasks at the same time. A recent study conducted on common wall lizards, Podarcis muralis, showed that lizards predominantly monitor a predator with the left eye while escaping. However, this work was conducted in a controlled laboratory setting owing to the difficulty of carrying out lateralization experiments under natural conditions. Nevertheless, field studies could provide important information to support what was previously found in the laboratory and demonstrate that these traits occur in nature. In this study, we conducted a field study on the antipredatory behavior of P. muralis lizards. We simulated predatory attacks on lizards in their natural environment. We found no lateralization in the measure of eye used by the lizard to monitor the predator before escaping from it, but the eye used was probably determined by the relative position of the lizard and the predator just before the attack. This first eye used did not affect escape decisions; lizards chose to escape toward the nearest refuge irrespective of whether it was located to the lizard’s left or right side. However, once they had escaped to a refuge, lizards had a left eye–mediated bias to monitor the predator when first emerging from the refuge, and this bias was likely independent of other environmental variables. Hence, these field findings support a left eye–mediated observation of the predator in P. muralis lizards, which confirms previous findings in this and other species.
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Maros, K., Boross, B., & Kubinyi, E. (2010). Approach and follow behaviour – possible indicators of the human-horse relationship. In Interaction Studies (Vol. 11, pp. 410–427).
Abstract: The aim of our study was to analyze the behavioural responses of horses (N = 51) to familiar humans and to find factors that may affect these responses in three tests: (1) approach to, (2) standing beside, and (3) following the familiar person. We investigated the impacts of horse-related factors (gender and age) and human-related factors (type of work, housing management, amount of handling, number of handlers and training to follow).<br xmlns=“http://pub2web.metastore.ingenta.com/ns/”></br> Horses with one handler needed less time to approach the human than horses with more handlers. Standing beside the human correlated positively with following. Following was mainly affected by training.<br xmlns=“http://pub2web.metastore.ingenta.com/ns/”></br> According to our results, the number of handlers has an important effect on horses' responses to familiar humans, especially regarding approach and follow behaviour. However, following behaviour is fundamentally determined by training.
Keywords: Approach; Follow; Human– Horse Interaction
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Llusia, D., Márquez, R., & Beltrán, J. F. (2010). Non-Selective and Time-Dependent Behavioural Responses of Common Toads (Bufo bufo) to Predator Acoustic Cues. Ethology, 116(12), 1146–1154.
Abstract: Abstract Acoustic predator recognition has rarely been studied in anurans, in spite of the fact that hearing is widespread in these animals and that it has been demonstrated to play an important role in both arthropods and other vertebrates. Using field playback experiments, we tested the hypothesis that adult common toads (Bufo bufo) are capable of recognizing natural vocalizations of a common predator, the Eurasian otter (Lutra lutra), and show antipredator responses. We found that toads exposed to both natural (two types of otter sounds) and synthetic stimuli [white noise (WN) and otter sound-based amplitude modulated WN] increased time allocated to locomotion and escape behaviour. These responses were correlated with time elapsed from sunset to the onset of testing and were independent from the type of acoustic signal, toad features and other environmental factors monitored. We conclude that B. bufo has not developed a selective recognition of predator vocalizations, suggesting that low-frequency or seismic sounds associated with predator movements may provide anurans with better cues about an approaching risk. We propose that the time-dependent response to acoustic stimuli of common toads represents a case of threat-sensitivity and demonstrates that it can occur even when the response to the threat is not predator specific.
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Lemasson, A., Koda, H., Kato, A., Oyakawa, C., Blois-Heulin, C., & Masataka, N. (2010). Influence of sound specificity and familiarity on Japanese macaques' (Macaca fuscata) auditory laterality. Behav. Brain. Res., 208(1), 286–289.
Abstract: Despite attempts to generalise the left hemisphere-speech association of humans to animal communication, the debate remains open. More studies on primates are needed to explore the potential effects of sound specificity and familiarity. Familiar and non-familiar nonhuman primate contact calls, bird calls and non-biological sounds were broadcast to Japanese macaques. Macaques turned their heads preferentially towards the left (right hemisphere) when hearing conspecific or familiar primates supporting hemispheric specialisation. Our results support the role of experience in brain organisation and the importance of social factors to understand laterality evolution.
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