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Author Tan, H.; Wilson, A.M. url  openurl
  Title Grip and limb force limits to turning performance in competition horses Type Journal Article
  Year 2011 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal  
  Volume 278 Issue 1715 Pages 2105-2111  
  Keywords  
  Abstract Manoeuverability is a key requirement for successful terrestrial locomotion, especially on variable terrain, and is a deciding factor in predator–prey interaction. Compared with straight-line running, bend running requires additional leg force to generate centripetal acceleration. In humans, this results in a reduction in maximum speed during bend running and a published model assuming maximum limb force as a constraint accurately predicts how much a sprinter must slow down on a bend given his maximum straight-line speed. In contrast, greyhounds do not slow down or change stride parameters during bend running, which suggests that their limbs can apply the additional force for this manoeuvre. We collected horizontal speed and angular velocity of heading of horses while they turned in different scenarios during competitive polo and horse racing. The data were used to evaluate the limits of turning performance. During high-speed turns of large radius horizontal speed was lower on the bend, as would be predicted from a model assuming a limb force limit to running speed. During small radius turns the angular velocity of heading decreased with increasing speed in a manner consistent with the coefficient of friction of the hoof–surface interaction setting the limit to centripetal force to avoid slipping.  
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  Notes (down) 10.1098/rspb.2010.2395 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5701  
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Author Bode, N.W.F.; Faria, J.J.; Franks, D.W.; Krause, J.; Wood, A.J. url  doi
openurl 
  Title How perceived threat increases synchronization in collectively moving animal groups Type Journal Article
  Year 2010 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. Roy. Soc. Lond. B Biol. Sci.  
  Volume 277 Issue 1697 Pages 3065-3070  
  Keywords  
  Abstract Nature is rich with many different examples of the cohesive motion of animals. Previous attempts to model collective motion have primarily focused on group behaviours of identical individuals. In contrast, we put our emphasis on modelling the contributions of different individual-level characteristics within such groups by using stochastic asynchronous updating of individual positions and orientations. Our model predicts that higher updating frequency, which we relate to perceived threat, leads to more synchronized group movement, with speed and nearest-neighbour distributions becoming more uniform. Experiments with three-spined sticklebacks (Gasterosteus aculeatus) that were exposed to different threat levels provide strong empirical support for our predictions. Our results suggest that the behaviour of fish (at different states of agitation) can be explained by a single parameter in our model: the updating frequency. We postulate a mechanism for collective behavioural changes in different environment-induced contexts, and explain our findings with reference to confusion and oddity effects.  
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  Notes (down) 10.1098/rspb.2010.0855 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5188  
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Author Bugnyar, T.; Stöwe, M.; Heinrich, B. doi  openurl
  Title Ravens, Corvus corax, follow gaze direction of humans around obstacles Type Journal Article
  Year 2004 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. Roy. Soc. Lond. B Biol. Sci.  
  Volume 271 Issue 1546 Pages 1331-1336  
  Keywords  
  Abstract The ability to follow gaze (i.e. head and eye direction) has recently been shown for social mammals, particularly primates. In most studies, individuals could use gaze direction as a behavioural cue without understanding that the view of others may be different from their own. Here, we show that hand–raised ravens not only visually co–orient with the look–ups of a human experimenter but also reposition themselves to follow the experimenter's gaze around a visual barrier. Birds were capable of visual co–orientation already as fledglings but consistently tracked gaze direction behind obstacles not before six months of age. These results raise the possibility that sub–adult and adult ravens can project a line of sight for the other person into the distance. To what extent ravens may attribute mental significance to the visual behaviour of others is discussed.  
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  Notes (down) 10.1098/rspb.2004.2738 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5009  
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Author Griffiths,S. W.; Brockmark, S.; Höjesjö,J.; Johnsson,J. I. doi  openurl
  Title Coping with divided attention: the advantage of familiarity Type Journal Article
  Year 2004 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. Roy. Soc. Lond. B Biol. Sci.  
  Volume 271 Issue 1540 Pages 695-699  
  Keywords  
  Abstract The ability of an animal to perform a task successfully is limited by the amount of attention being simultaneously focused on other activities. One way in which individuals might reduce the cost of divided attention is by preferentially focusing on the most beneficial tasks. In territorial animals where aggression is lower among familiar individuals, the decision to associate preferentially with familiar conspecifics may therefore confer advantages by allowing attention to be switched from aggression to predator vigilance and feeding. Wild juvenile brown trout were used to test the prediction that familiar fishes respond more quickly than unfamiliar fishes to a simulated predator attack. Our results confirm this prediction by demonstrating that familiar trout respond 14% faster than unfamiliar individuals to a predator attack. The results also show that familiar fishes consume a greater number of food items, foraging at more than twice the rate of unfamiliar conspecifics. To the best of our knowledge, these results provide the first evidence that familiarity–biased association confers advantages through the immediate fitness benefits afforded by faster predator–evasion responses and the long–term benefits provided by increased feeding opportunities.  
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  Notes (down) 10.1098/rspb.2003.2648 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5007  
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Author Garamszegi, L.Z.; Møller, A.P.; Erritzøe, J. doi  openurl
  Title Coevolving avian eye size and brain size in relation to prey capture and nocturnality Type Journal Article
  Year 2002 Publication Proceedings of the Royal Society of London. Series B: Biological Sciences Abbreviated Journal Proc Roy Soc Lond B Biol Sci  
  Volume 269 Issue 1494 Pages 961-967  
  Keywords adaptation; behaviour; brain size; coevolution; eye size; vision  
  Abstract Behavioural adaptation to ecological conditions can lead to brain size evolution. Structures involved in behavioural visual information processing are expected to coevolve with enlargement of the brain. Because birds are mainly vision–oriented animals, we tested the predictions that adaptation to different foraging constraints can result in eye size evolution, and that species with large eyes have evolved large brains to cope with the increased amount of visual input. Using a comparative approach, we investigated the relationship between eye size and brain size, and the effect of prey capture technique and nocturnality on these traits. After controlling for allometric effects, there was a significant, positive correlation between relative brain size and relative eye size. Variation in relative eye and brain size were significantly and positively related to prey capture technique and nocturnality when a potentially confounding variable, aquatic feeding, was controlled statistically in multiple regression of independent linear contrasts. Applying a less robust, brunching approach, these patterns also emerged, with the exception that relative brain size did not vary with prey capture technique. Our findings suggest that relative eye size and brain size have coevolved in birds in response to nocturnal activity and, at least partly, to capture of mobile prey.  
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  Notes (down) 10.1098/rspb.2002.1967 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5452  
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Author Johnstone, R.A.; Dugatkin, L.A. url  doi
openurl 
  Title Coalition formation in animals and the nature of winner and loser effects Type Journal Article
  Year 2000 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. Roy. Soc. Lond. B Biol. Sci.  
  Volume 267 Issue 1438 Pages 17-21  
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  Abstract Coalition formation has been documented in a diverse array of taxa, yet there has been little formal analysis of polyadic interactions such as coalitions. Here, we develop an optimality model which examines the role of winner and loser effects in shaping coalition formation. We demonstrate that the predicted patterns of alliances are strongly dependent on the way in which winner and loser effects change with contestant strength. When winner and loser effects decrease with the resource-holding power (RHP) of the combatants, coalitions will be favoured between the strongest members of a group, but not between the weakest. If, in contrast, winner and loser effects increase with RHP, exactly the opposite predictions emerge. All other things being equal, intervention is more likely to prove worthwhile when the beneficiary of the aid is weaker (and its opponent is stronger), because the beneficiary is then less likely to win without help. Consequently, intervention is more probable when the impact of victory on the subsequent performance of a combatant increases with that individual's strength because this selects for intervention in favour of weaker combatants. The published literature on hierarchy formation does not reveal how winner and loser effects actually change with contestant strength and we therefore hope that our model will spur others to collect such data; in this light we suggest an experiment which will help to elucidate the nature of winner and loser effects and their impact on coalition formation in animals.  
  Address * aggression * dominance * hierarchy * intervention * reciprocity  
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  Notes (down) 10.1098/rspb.2000.0960 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5290  
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Author Dugatkin, L.A. url  doi
openurl 
  Title Breaking up fights between others: a model of intervention behaviour Type Journal Article
  Year 1998 Publication Proceedings of the Royal Society of London. Series B: Biological Sciences Abbreviated Journal Proc. R. Soc. Lond. B  
  Volume 265 Issue 1394 Pages 433-437  
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  Abstract To examine when and why animals break up fights between others in their group, I modelled whether ‘winner’ and ‘loser’ effects might be one element driving the evolution of intervention behaviour. I considered one particular type of intervention: when the intervener simply breaks up fights between two others, but does not favour either party in so doing. When victories at time T + 1 are more likely given a victory at time T (i.e. winner effects), intervention is often favoured. Intervention is favoured in these circumstances because the intervening party in essence stops others from ‘getting on a roll’ and climbing up any hierarchy that exists. However, when loser effects alone are at work (defeats at time T + 1 are more likely given a defeat at time T), breaking up fights between others is never selected. If both winner and loser effects are operating simultaneously, then the likelihood of intervention behaviour evolving is a function of the relative strength of these two effects. The greater the winner effect relative to the loser effect, the more likely intervention behaviour is to evolve.  
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  Notes (down) 10.1098/rspb.1998.0313 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5240  
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Author Drea, C.M.; Wallen, K. url  openurl
  Title Low-status monkeys “play dumb” when learning in mixed social groups Type Journal Article
  Year 1999 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 96 Issue 22 Pages 12965-12969  
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  Abstract Many primates, including humans, live in complex hierarchical societies where social context and status affect daily life. Nevertheless, primate learning studies typically test single animals in limited laboratory settings where the important effects of social interactions and relationships cannot be studied. To investigate the impact of sociality on associative learning, we compared the individual performances of group-tested rhesus monkeys (Macaca mulatta) across various social contexts. We used a traditional discrimination paradigm that measures an animal's ability to form associations between cues and the obtaining of food in choice situations; but we adapted the task for group testing. After training a 55-member colony to separate on command into two subgroups, composed of either high- or low-status families, we exposed animals to two color discrimination problems, one with all monkeys present (combined condition), the other in their “dominant” and “subordinate” cohorts (split condition). Next, we manipulated learning history by testing animals on the same problems, but with the social contexts reversed. Monkeys from dominant families excelled in all conditions, but subordinates performed well in the split condition only, regardless of learning history. Subordinate animals had learned the associations, but expressed their knowledge only when segregated from higher-ranking animals. Because aggressive behavior was rare, performance deficits probably reflected voluntary inhibition. This experimental evidence of rank-related, social modulation of performance calls for greater consideration of social factors when assessing learning and may also have relevance for the evaluation of human scholastic achievement.  
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  Notes (down) 10.1073/pnas.96.22.12965 Approved no  
  Call Number Serial 2093  
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Author Leadbeater, E.; Dawson, E.H. url  openurl
  Title A social insect perspective on the evolution of social learning mechanisms Type Journal Article
  Year 2017 Publication Proceedings of the National Academy of Sciences Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 114 Issue 30 Pages 7838-7845  
  Keywords  
  Abstract The social world offers a wealth of opportunities to learn from others, and across the animal kingdom individuals capitalize on those opportunities. Here, we explore the role of natural selection in shaping the processes that underlie social information use, using a suite of experiments on social insects as case studies. We illustrate how an associative framework can encompass complex, context-specific social learning in the insect world and beyond, and based on the hypothesis that evolution acts to modify the associative process, suggest potential pathways by which social information use could evolve to become more efficient and effective. Social insects are distant relatives of vertebrate social learners, but the research we describe highlights routes by which natural selection could coopt similar cognitive raw material across the animal kingdom.  
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  Notes (down) 10.1073/pnas.1620744114 Approved no  
  Call Number Equine Behaviour @ team @ Serial 6189  
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Author Biegler, R.; McGregor, A.; Krebs, J.R.; Healy, S.D. url  doi
openurl 
  Title A larger hippocampus is associated with longer-lasting spatial memory Type Journal Article
  Year 2001 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 98 Issue 12 Pages 6941-6944  
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  Abstract Volumetric studies in a range of animals (London taxi-drivers, polygynous male voles, nest-parasitic female cowbirds, and a number of food-storing birds) have shown that the size of the hippocampus, a brain region essential to learning and memory, is correlated with tasks involving an extra demand for spatial learning and memory. In this paper, we report the quantitative advantage that food storers gain from such an enlargement. Coal tits () a food-storing species, performed better than great tits (), a nonstoring species, on a task that assessed memory persistence but not on a task that assessed memory resolution or on one that tested memory capacity. These results show that the advantage to the food-storing species associated with an enlarged hippocampus is one of memory persistence.  
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  Notes (down) 10.1073/pnas.121034798 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4743  
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