Is Leadership a Reliable Concept in Animals? An Empirical Study in the Horse

Leadership is commonly invoked when accounting for the coordination of group movements in animals, yet it remains loosely defined. In parallel, there is increased evidence of the sharing of group decisions by animals on the move. How leadership integrates within this recent framework on collective decision-making is unclear. Here, we question the occurrence of leadership in horses, a species in which this concept is of prevalent use. The relevance of the three main definitions of leadership – departing first, walking in front travel position, and eliciting the joining of mates – was tested on the collective movements of two semi-free ranging groups of Przewalski horses (Equus ferus przewalskii). We did not find any leader capable of driving most group movements or recruiting mates more quickly than others. Several group members often displayed pre-departure behaviours at the same time, and the simultaneous departure of several individuals was common. We conclude that the decision-making process was shared by several group members a group movement (i.e., partially shared consensus) and that the leadership concept did not help to depict individual departure and leading behaviour across movements in both study groups. Rather, the different proxies of leadership produced conflicting information about individual contributions to group coordination. This study discusses the implications of these findings for the field of coordination and decision-making research.

[1]  Simona Cafazzo,et al.  Effect of affiliative and agonistic relationships on leadership behaviour in free-ranging dogs , 2010, Animal Behaviour.

[2]  B. Thierry,et al.  Decision making in group departures of sheep is a continuous process , 2009, Animal Behaviour.

[3]  Andrew J. King,et al.  Dominance and Affiliation Mediate Despotism in a Social Primate , 2008, Current Biology.

[4]  Myriam Maumy,et al.  Decision-Making in Przewalski Horses (Equus ferus przewalskii) is Driven by the Ecological Contexts of Collective Movements , 2009 .

[5]  Adaptive explanation in socio‐ecology: lessons from the Equidae , 2000, Biological reviews of the Cambridge Philosophical Society.

[6]  Rufus A. Johnstone,et al.  Temperament and Hunger Interact to Determine the Emergence of Leaders in Pairs of Foraging Fish , 2012, PloS one.

[7]  M. Tomasello,et al.  Shared intentionality. , 2007, Developmental science.

[8]  T. Vicsek,et al.  Hierarchical group dynamics in pigeon flocks , 2010, Nature.

[9]  Jens Krause,et al.  Leadership and social information use in human crowds , 2010, Animal Behaviour.

[10]  Rufus A. Johnstone,et al.  Initiative, Personality and Leadership in Pairs of Foraging Fish , 2012, PloS one.

[11]  J. Deneubourg,et al.  How many for dinner? Recruitment and monitoring by glances in capuchins , 2007, Primates.

[12]  Tamás Vicsek,et al.  Modeling the Emergence of Modular Leadership Hierarchy During the Collective Motion of Herds Made of Harems , 2015 .

[13]  D. Réale,et al.  Predator-induced natural selection on temperament in bighorn ewes , 2003, Animal Behaviour.

[14]  B. Thierry,et al.  Decision-making processes in group departures of cattle. , 2009 .

[15]  C. Sueur,et al.  Reaching a Consensus: Terminology and Concepts Used in Coordination and Decision-Making Research , 2011, International Journal of Primatology.

[16]  L. Mech,et al.  Leadership behavior in relation to dominance and reproductive status in gray wolves, Canis lupus , 2002 .

[17]  J. Gautrais,et al.  Collective decision-making in white-faced capuchin monkeys , 2009, Proceedings of the Royal Society B: Biological Sciences.

[18]  C. Sueur,et al.  Shared or unshared consensus for collective movement? Towards methodological concerns , 2010, Behavioural Processes.

[19]  J. Krause,et al.  Relationship between the position preference and nutritional state of individuals in schools of juvenile roach (Rutilus rutilus) , 1992, Behavioral Ecology and Sociobiology.

[20]  M. van vugt,et al.  Leadership, followership, and evolution: some lessons from the past. , 2008, The American psychologist.

[21]  Joan B. Silk,et al.  On the Move. How and Why Animals Travel in Groups. , 2000 .

[22]  Dominic D. P. Johnson,et al.  The Origins and Evolution of Leadership , 2009, Current Biology.

[23]  S. Tyler.  The Behaviour and Social Organization of the New Forest Ponies , 1972 .

[24]  Tamás Vicsek,et al.  Leadership and Path Characteristics during Walks Are Linked to Dominance Order and Individual Traits in Dogs , 2014, PLoS Comput. Biol..

[25]  D. Zinner,et al.  To follow or not to follow: decision making and leadership during the morning departure in chacma baboons , 2008, Animal Behaviour.

[26]  K. Oers,et al.  Personality differences explain leadership in barnacle geese , 2009, Animal Behaviour.

[27]  Jean-Louis Deneubourg,et al.  Differences in Nutrient Requirements Imply a Non-Linear Emergence of Leaders in Animal Groups , 2010, PLoS Comput. Biol..

[28]  O. Petit,et al.  Distributed leadership in semifree-ranging white-faced capuchin monkeys , 2003, Animal Behaviour.

[29]  Konstanze Krueger,et al.  Movement initiation in groups of feral horses , 2014, Behavioural Processes.

[30]  Jens Krause,et al.  Accurate decisions in an uncertain world: collective cognition increases true positives while decreasing false positives , 2013, Proceedings of the Royal Society B: Biological Sciences.

[31]  C. Sueur,et al.  Signals use by leaders in Macaca tonkeana and Macaca mulatta: group-mate recruitment and behaviour monitoring , 2010, Animal Cognition.

[32]  J. Berger.  Organizational systems and dominance in feral horses in the Grand Canyon , 1977, Behavioral Ecology and Sociobiology.

[33]  The Mountain Gorilla: Ecology and Behavior , 1963 .

[34]  Kay E. Holekamp,et al.  Group travel in social carnivores , 2000 .

[35]  M. Visser,et al.  Spatial and temporal variation in the relative contribution of density dependence, climate variation and migration to fluctuations in the size of great tit populations. , 2009, The Journal of animal ecology.

[36]  F. James Rohlf,et al.  Biometry: The Principles and Practice of Statistics in Biological Research , 1969 .

[37]  M. Tomasello,et al.  Understanding and sharing intentions: The origins of cultural cognition , 2005, Behavioral and Brain Sciences.

[38]  Andrew J. King,et al.  Where Next? Group Coordination and Collective Decision Making by Primates , 2011, International Journal of Primatology.

[39]  Ilya R. Fischhoff,et al.  Social relationships and reproductive state influence leadership roles in movements of plains zebra, Equus burchellii , 2007, Animal Behaviour.

[40]  S. Pratt,et al.  Quorum responses and consensus decision making , 2009, Philosophical Transactions of the Royal Society B: Biological Sciences.

[41]  Weikang Yang,et al.  Reintroduction of Przewalski's horse (Equus ferus przewalskii) in Xinjiang, China: The status and experience , 2014 .

[42]  M. Hausberger,et al.  Adult-Young Ratio, a Major Factor Regulating Social Behaviour of Young: A Horse Study , 2009, PloS one.

[43]  Andrew J. King,et al.  Follow me! I’m a leader if you do; I’m a failed initiator if you don’t? , 2010, Behavioural Processes.

[44]  H. Kummer,et al.  Social Organization of Hamadryas Baboons: A Field Study , 1967 .

[45]  L. Conradt,et al.  Consensus decision making in animals. , 2005, Trends in ecology & evolution.

[46]  John G. Robinson.  On the Move. How and Why Animals Travel in Groups , 2000, Animal Behaviour.

[47]  Andrea Manica,et al.  Evolution of personality differences in leadership , 2011, Proceedings of the National Academy of Sciences.

[48]  D. McCullough,et al.  Behavior patterns and communication in feral horses. , 2010, Zeitschrift fur Tierpsychologie.

[49]  C. Feh.  Relationships and communication in socially natural horse herds , 2005 .

[50]  Effects of fly disturbance on the behaviour of a population of reintroduced Przewalski horses (Equus ferus przewalskii) in Mongolia , 2010 .

[51]  Romain Julliard,et al.  Time budget-, behavioral synchrony- and body score development of a newly released Przewalski's horse group Equus ferus przewalskii, in the Great Gobi B Strictly Protected Area in SW Mongolia. , 2007, Applied animal behaviour science.

[52]  S. G. Reebs.  Can a minority of informed leaders determine the foraging movements of a fish shoal? , 2000, Animal Behaviour.

[53]  R. Johnstone,et al.  The emergence of leaders and followers in foraging pairs when the qualities of individuals differ , 2008, BMC Evolutionary Biology.

[54]  Marek Špinka,et al.  Graded leadership by dominant animals in a herd of female beef cattle on pasture , 2010, Animal Behaviour.

[55]  Viktor Reinhardt,et al.  MOVEMENT ORDERS AND LEADERSHIP IN A SEMI-WILD CATTLE HERD , 1983 .

[56]  O. Petit,et al.  Decision-making processes: The case of collective movements , 2010, Behavioural Processes.

[57]  R. Johnstone,et al.  Social Feedback and the Emergence of Leaders and Followers , 2009, Current Biology.

[58]  C. Fureix,et al.  Exploring aggression regulation in managed groups of horses Equus caballus , 2012 .

[59]  R. Byrne,et al.  Social relationships of mountain baboons: Leadership and affiliation in a non‐female‐bonded monkey , 1989, American journal of primatology.

[60]  Jean-Louis Deneubourg,et al.  Self-Organization in Primates: Understanding the Rules Underlying Collective Movements , 2011, International Journal of Primatology.

[61]  O. Petit,et al.  Shared or unshared consensus decision in macaques? , 2008, Behavioural Processes.

[62]  Guy Cowlishaw,et al.  When to use social information: the advantage of large group size in individual decision making , 2007, Biology Letters.

[63]  Sean A. Rands,et al.  Spontaneous emergence of leaders and followers in foraging pairs , 2003, Nature.

[64]  Charlotte K. Hemelrijk,et al.  Leadership in fish shoals , 2000 .

[65]  Christian List,et al.  Democracy in animal groups: a political science perspective. , 2004, Trends in ecology & evolution.

[66]  Jacques Gautrais,et al.  Moving together: Incidental leaders and naïve followers , 2010, Behavioural Processes.

[67]  Bertrand Dumont,et al.  Consistency of animal order in spontaneous group movements allows the measurement of leadership in a group of grazing heifers , 2005 .

[68]  I. Couzin,et al.  Effective leadership and decision-making in animal groups on the move , 2005, Nature.

[69]  J. Lamprecht.  What makes an individual the leader of its group? An evolutionary concept of distance regulation and leadership , 1996 .