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Author Weissing, F.J. url  doi
openurl 
  Title Animal behaviour: Born leaders Type Journal Article
  Year 2011 Publication Abbreviated Journal Nature  
  Volume (down) 474 Issue 7351 Pages 288-289  
  Keywords * Animal behaviour * Evolution * Psychology  
  Abstract Social animals face a dilemma. To reap the benefits of group living, they have to stay together. However, individuals differ in their preferences as to where to go and what to do next. If all individuals follow their own preferences, group coherence is undermined, resulting in an outcome that is unfavourable for everyone. Neglecting one's own preferences and following a leader is one way to resolve this coordination problem. But what attributes make an individual a 'leader'? A modelling study by Johnstone and Manica1 illuminates this question.  
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  Publisher Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved. Place of Publication Editor  
  Language Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 0028-0836 ISBN Medium  
  Area Expedition Conference  
  Notes 10.1038/474288a Approved no  
  Call Number Equine Behaviour @ team @ Serial 5396  
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Author Van Schaik, C.P.; Burkart, J.M. url  doi
openurl 
  Title Social learning and evolution: the cultural intelligence hypothesis Type Journal Article
  Year 2011 Publication Philos Trans R Soc B Abbreviated Journal  
  Volume (down) 366 Issue Pages  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Van Schaik2011 Serial 6227  
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Author Bartal, I.B.-A.; Decety, J.; Mason, P. url  doi
openurl 
  Title Empathy and Pro-Social Behavior in Rats Type Journal Article
  Year 2011 Publication Science Abbreviated Journal Science  
  Volume (down) 334 Issue 6061 Pages 1427-1430  
  Keywords  
  Abstract Whereas human pro-social behavior is often driven by empathic concern for another, it is unclear whether nonprimate mammals experience a similar motivational state. To test for empathically motivated pro-social behavior in rodents, we placed a free rat in an arena with a cagemate trapped in a restrainer. After several sessions, the free rat learned to intentionally and quickly open the restrainer and free the cagemate. Rats did not open empty or object-containing restrainers. They freed cagemates even when social contact was prevented. When liberating a cagemate was pitted against chocolate contained within a second restrainer, rats opened both restrainers and typically shared the chocolate. Thus, rats behave pro-socially in response to a conspecific�s distress, providing strong evidence for biological roots of empathically motivated helping behavior.  
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  Notes 10.1126/science.1210789 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5725  
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Author Gesquiere, L.R.; Learn, N.H.; Simao, M.C.M.; Onyango, P.O.; Alberts, S.C.; Altmann, J. url  doi
openurl 
  Title Life at the Top: Rank and Stress in Wild Male Baboons Type Journal Article
  Year 2011 Publication Science Abbreviated Journal  
  Volume (down) 333 Issue 6040 Pages 357-360  
  Keywords  
  Abstract In social hierarchies, dominant individuals experience reproductive and health benefits, but the costs of social dominance remain a topic of debate. Prevailing hypotheses predict that higher-ranking males experience higher testosterone and glucocorticoid (stress hormone) levels than lower-ranking males when hierarchies are unstable but not otherwise. In this long-term study of rank-related stress in a natural population of savannah baboons (Papio cynocephalus), high-ranking males had higher testosterone and lower glucocorticoid levels than other males, regardless of hierarchy stability. The singular exception was for the highest-ranking (alpha) males, who exhibited both high testosterone and high glucocorticoid levels. In particular, alpha males exhibited much higher stress hormone levels than second-ranking (beta) males, suggesting that being at the very top may be more costly than previously thought.  
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  Notes 10.1126/science.1207120 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5655  
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Author Bugnyar, T. url  doi
openurl 
  Title Knower–guesser differentiation in ravens: others' viewpoints matter Type Journal Article
  Year 2011 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. Roy. Soc. Lond. B Biol. Sci.  
  Volume (down) 278 Issue 1705 Pages 634-640  
  Keywords  
  Abstract Differentiating between individuals with different knowledge states is an important step in child development and has been considered as a hallmark in human evolution. Recently, primates and corvids have been reported to pass knower–guesser tasks, raising the possibility of mental attribution skills in non-human animals. Yet, it has been difficult to distinguish ‘mind-reading’ from behaviour-reading alternatives, specifically the use of behavioural cues and/or the application of associatively learned rules. Here, I show that ravens (Corvus corax) observing an experimenter hiding food are capable of predicting the behaviour of bystanders that had been visible at both, none or just one of two caching events. Manipulating the competitors' visual field independently of the view of the test-subject resulted in an instant drop in performance, whereas controls for behavioural cues had no such effect. These findings indicate that ravens not only remember whom they have seen at caching but also take into account that the other's view was blocked. Notably, it does not suffice for the birds to associate specific competitors with specific caches. These results support the idea that certain socio-ecological conditions may select for similar cognitive abilities in distantly related species and that some birds have evolved analogous precursors to a human theory-of-mind.  
  Address raven; Corvus corax; knowledge attribution; perspective; competitive food retrieval; caching  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5287  
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Author Melis, A.P.; Warneken, F.; Jensen, K.; Schneider, A.-C.; Call, J.; Tomasello, M. url  doi
openurl 
  Title Chimpanzees help conspecifics obtain food and non-food items Type Journal Article
  Year 2011 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal  
  Volume (down) 278 Issue 1710 Pages 1405-1413  
  Keywords  
  Abstract Chimpanzees (Pan troglodytes) sometimes help both humans and conspecifics in experimental situations in which immediate selfish benefits can be ruled out. However, in several experiments, chimpanzees have not provided food to a conspecific even when it would cost them nothing, leading to the hypothesis that prosociality in the food-provisioning context is a derived trait in humans. Here, we show that chimpanzees help conspecifics obtain both food and non-food items—given that the donor cannot get the food herself. Furthermore, we show that the key factor eliciting chimpanzees' targeted helping is the recipients' attempts to either get the food or get the attention of the potential donor. The current findings add to the accumulating body of evidence that humans and chimpanzees share the motivation and skills necessary to help others in situations in which they cannot selfishly benefit. Humans, however, show prosocial motives more readily and in a wider range of contexts.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5630  
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Author McComb, K.; Shannon, G.; Durant, S.M.; Sayialel, K.; Slotow, R.; Poole, J.; Moss, C. url  doi
openurl 
  Title Leadership in elephants: the adaptive value of age Type Journal Article
  Year 2011 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. R. Soc. Lond. B.  
  Volume (down) 278 Issue 1722 Pages 3270-3276  
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  Abstract The value of age is well recognized in human societies, where older individuals often emerge as leaders in tasks requiring specialized knowledge, but what part do such individuals play in other social species? Despite growing interest in how effective leadership might be achieved in animal social systems, the specific role that older leaders may play in decision-making has rarely been experimentally investigated. Here, we use a novel playback paradigm to demonstrate that in African elephants (Loxodonta africana), age affects the ability of matriarchs to make ecologically relevant decisions in a domain critical to survival—the assessment of predatory threat. While groups consistently adjust their defensive behaviour to the greater threat of three roaring lions versus one, families with younger matriarchs typically under-react to roars from male lions despite the severe danger they represent. Sensitivity to this key threat increases with matriarch age and is greatest for the oldest matriarchs, who are likely to have accumulated the most experience. Our study provides the first empirical evidence that individuals within a social group may derive significant benefits from the influence of an older leader because of their enhanced ability to make crucial decisions about predatory threat, generating important insights into selection for longevity in cognitively advanced social mammals.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5652  
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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 (down) 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 10.1098/rspb.2010.2395 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5701  
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Author Mesterton-Gibbons, M.; Gavrilets, S.; Gravner, J.; Akçay, E. url  doi
openurl 
  Title Models of coalition or alliance formation Type Journal Article
  Year 2011 Publication Journal of Theoretical Biology Abbreviated Journal J. Theor. Biol.  
  Volume (down) 274 Issue 1 Pages 187-204  
  Keywords Game theory; Cooperation  
  Abstract More than half a century has now elapsed since coalition or alliance formation theory (CAFT) was first developed. During that time, researchers have amassed a vast amount of detailed and high-quality data on coalitions or alliances among primates and other animals. But models have not kept pace, and more relevant theory is needed. In particular, even though CAFT is primarily an exercise in polyadic game theory, game theorists have devoted relatively little attention to questions that motivate field research, and much remains largely unexplored. The state of the art is both a challenge and an opportunity. In this review we describe a variety of game-theoretic and related modelling approaches that have much untapped potential to address the questions that field biologists ask.  
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  Series Volume Series Issue Edition  
  ISSN 0022-5193 ISBN Medium  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5322  
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Author Clayton, H.M.; Larson, B.; Kaiser, L.A.J.; Lavagnino, M. url  doi
openurl 
  Title Length and elasticity of side reins affect rein tension at trot Type Journal Article
  Year 2011 Publication The Veterinary Journal Abbreviated Journal  
  Volume (down) 188 Issue 3 Pages 291-294  
  Keywords Horse; Equitation; Training; Rein aids  
  Abstract This study investigated the horse’s contribution to tension in the reins. The experimental hypotheses were that tension in side reins (1) increases biphasically in each trot stride, (2) changes inversely with rein length, and (3) changes with elasticity of the reins. Eight riding horses trotted in hand at consistent speed in a straight line wearing a bit and bridle and three types of side reins (inelastic, stiff elastic, compliant elastic) were evaluated in random order at long, neutral, and short lengths. Strain gauge transducers (240 Hz) measured minimal, maximal and mean rein tension, rate of loading and impulse. The effects of rein type and length were evaluated using ANOVA with Bonferroni post hoc tests. Rein tension oscillated in a regular pattern with a peak during each diagonal stance phase. Within each rein type, minimal, maximal and mean tensions were higher with shorter reins. At neutral or short lengths, minimal tension increased and maximal tension decreased with elasticity of the reins. Short, inelastic reins had the highest maximal tension and rate of loading. Since the tension variables respond differently to rein elasticity at different lengths, it is recommended that a set of variables representing different aspects of rein tension should be reported.  
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  Series Volume Series Issue Edition  
  ISSN 1090-0233 ISBN Medium  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 6124  
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