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Author Gueron, S.; Levin, S.A.; Rubenstein, D.I. url  doi
openurl 
  Title The Dynamics of Herds: From Individuals to Aggregations Type Journal Article
  Year 1996 Publication Journal of Theoretical Biology Abbreviated Journal J. Theor. Biol.  
  Volume 182 Issue 1 Pages 85-98  
  Keywords  
  Abstract The dynamic behavior of small herds is investigated by means of simulations of two-dimensional discrete-stochastic models. An individual-based approach is used to relate collective behavior to individual decisions. In our model, the motion of an individual in a herd is assumed to be the combined result of both density-independent and density-dependent decisions, in the latter case based on the influence of surrounding neighbors; assumed decision rules are hierarchical, balancing short range repulsion against long-range attraction. The probability of fragmentation of the model herd depends on parameter values. We explore the variety and characteristics of spatial patterns that develop during migration, for herds that are homogeneous and heterogeneous regarding intrinsic walking speeds. Group integrity can be maintained even in mixed populations, but fragmentation results for these more easily than for a homogeneous herd. Observations of natural populations suggest that animals move away from individuals that intrude too closely into their environment, but are attracted to individuals at a distance. Between these extremes, there appears to be a neutral zone, within which other individuals engender no response. We explore the importance of this neutral zone, and offer evolutionary interpretations. In particular, the neutral zone, if not too large, permits the individual to remain in contact with the herd, while reducing the frequency with which acceleration or deceleration must be undertaken. This offers obvious energetic benefits.  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-5193 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 5253  
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Author Parker, G.A.; Rubenstein, D.I. url  doi
openurl 
  Title Role assessment, reserve strategy, and acquisition of information in asymmetric animal conflicts Type Journal Article
  Year 1981 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.  
  Volume 29 Issue 1 Pages 221-240  
  Keywords  
  Abstract It was formerly argued that alternative evolutionarily stable strategies (ESSs) are possible for animal contests characterized by some asymmetry that can be perceived with perfect accuracy. Where roles A and B refer to the asymmetry between opponents, ESSs are: [`]fight when A, retreat when B', and vice versa. Either can be an ESS, but only if the [`]reserve strategy' (=what an animal does when it fights) is sufficiently damaging. We examine the [`]war of attrition' (winner = opponent that persists longer). In a population at either ESS, reserve strategy is never normally shown; it is therefore subject to drift unless the selective action of rare individuals which break the convention is considered. These could arise either by mutation or by mistakes in role assessment. When mutations and mistakes simply specify that occasionally an animal fights when it [`]should' retreat, selection adjusts reserve strategy to a level where only one ESS (the [`]commonsense' ESS) is possible, if the asymmetry is relevant to payoff. Thus for asymmetries in fighting ability or resource value, the individual with the lower score will retreat. However, we are particularly concerned with cases where both payoff-relevant aspects (fighting ability and resource value) are asymmetric. If opponents sustain contest costs at rates KA and KB, and their resource values are VA and VB, an [`]optimal assessor' strategy defined by the interaction between the two asymmetries, is a unique ESS. It obeys the rule [`]fight on estimating role A, where VA/KA>VB/KB; retreat in B'. If mistakes can occur in both roles, but are very rate, the ESS is not fundamentally altered though there will be infinitesimal tendencies for persisting in role B. Selection to improve assessment abilities intensifies as abilities improve, but is weak if roles A and B are rather similar. Over a range of similarity between roles, an [`]owner wins' convention may be adopted if ownership correlates positively with role A and an individual cannot tell when it would otherwise pay him to break the convention. We also examine a contest in which information about roles can be acquired only during a contest itself, and at a cost. Much depends on the rate at which information is acquired relative to the rate at which costs are expended, and on whether contests normally escalate in intensity, remain at the same level, or de-escalate. Selection favours short contests when costs are high relative to resource value, where the outcome of a round contains much information about fighting ability, and where the actual disparity in fighting ability is large.  
  Address  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-3472 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 5325  
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Author Rubenstein, D. pdf  openurl
  Title Wild Equid Movements: Impacts of Habitat Quality, Predation Pressure and Leadership Type Conference Article
  Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg  
  Volume in press Issue Pages  
  Keywords  
  Abstract Animals spend much of their lives on the move searching for food, shelter and mates. As long-legged, large bodied species, equids are well suited for traveling long distances. Understanding where free-ranging equids go, why they choose particular locations, some near and some far, and what impact such movements have on patterns of sociality, demography and human livelihoods are only now coming into focus. This talk will explore how bottom-up factors, such as the abundance and distribution of key resources, and top-down factors, such as the type and location of predators, interact to shape overall movement patterns of equids, how leadership roles develop and what outcomes such movements are likely to have on human activities.  
  Address  
  Corporate Author Rubenstein, D. Thesis  
  Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 978-3-9808134-26 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 5556  
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Author Rubenstein, D. pdf  isbn
openurl 
  Title Social Networks: Linking Form with Function in Equid Societies Type Conference Article
  Year 2015 Publication Proceedings of the 3. International Equine Science Meeting Abbreviated Journal Proc. 3. Int. Equine. Sci. Mtg  
  Volume Issue Pages  
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  Abstract Animal societies develop from interactions and relationships that occur among individuals within populations. The fundamental tenet of behavioral ecology is that ecological factors shape behavior and determine the distribution and associations of individuals on landscapes. As a result, different social systems emerge in different habitats and under different environmental conditions. Since characterizing social systems depends on time and motion studies of individual actions and interactions that are often bilateral, such characterizations are often coarse-grained. If social relationships can be characterized using social networks, however, seemingly similar social organizations often reveal informative differences in terms of deep structure. Thus social network theory should be able to provide insights in to the connections between social form and function. This talk will explore how the network structures of horses, zebras and asses can provide novel insights into the functioning of animal societies with respect to the spread of memes, genes and diseases.  
  Address  
  Corporate Author Rubenstein, D. Thesis  
  Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title Proc. 3. Int. Equine. Sci. Mtg  
  Series Volume in prep Series Issue Edition  
  ISSN ISBN 978-3-95625-000-2 Medium  
  Area Expedition Conference  
  Notes Id - Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 5797  
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Author Zhang, Y.; Cao, Q.S.; Rubenstein, D.I.; Zang, S.; Songer, M.; Leimgruber, P.; Chu, H.; Cao, J.; Li, K.; Hu, D. url  doi
openurl 
  Title Water Use Patterns of Sympatric Przewalski's Horse and Khulan: Interspecific Comparison Reveals Niche Differences Type Journal Article
  Year 2015 Publication Plos One Abbreviated Journal Plos One  
  Volume 10 Issue 7 Pages e0132094  
  Keywords  
  Abstract Acquiring water is essential for all animals, but doing so is most challenging for desert-living animals. Recently Przewalski's horse has been reintroduced to the desert area in China where the last wild surviving member of the species was seen before it vanished from China in the1960s. Its reintroduction placed it within the range of a close evolutionary relative, the con-generic Khulan. Determining whether or not these two species experience competition and whether or not such competition was responsible for the extinction of Przewalski's horses in the wild over 50 years ago, requires identifying the fundamental and realized niches of both species. We remotely monitored the presence of both species at a variety of water points during the dry season in Kalamaili Nature Reserve, Xinjiang, China. Przewalski's horses drank twice per day mostly during daylight hours at low salinity water sources while Khulans drank mostly at night usually at high salinity water points or those far from human residences. Spatial and temporal differences in water use enables coexistence, but suggest that Przewalski's horses also restrict the actions of Khulan. Such differences in both the fundamental and realized niches were associated with differences in physiological tolerances for saline water and human activity as well as differences in aggression and dominance.  
  Address  
  Corporate Author Thesis  
  Publisher Public Library of Science Place of Publication Editor  
  Language Summary Language Original Title  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 6377  
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Author Fischhoff, I.R.; Sundaresan, S.R.; Cordingley, J.; Larkin, H.M.; Sellier, M.-J.; Rubenstein, D.I. url  doi
openurl 
  Title Social relationships and reproductive state influence leadership roles in movements of plains zebra, Equus burchellii Type Journal Article
  Year 2007 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.  
  Volume 73 Issue 5 Pages 825-831  
  Keywords collective movements; drinking; equid; Equus burchellii; foraging; group dynamics; motivation; plains zebra; reproductive status; social relationships  
  Abstract In animal groups, collective movements emerge from individual interactions. Biologists seek to identify how characteristics of actors in these groups, and their relationships, influence the decision-making process. We distinguished two basic factors determining leadership in group choices: identity and state. We hypothesized that identity is more important to leadership in groups with stable relationships, which permit the development of habitual roles. In groups with fluid membership, particular individuals or subgroups are less likely to emerge as consistent leaders. Instead, we predicted that movement initiation in unstable groups depends on individual state at the time of the decision. We characterized how identity and reproductive state influenced leadership patterns in the movements of plains zebra. As in many other mammals, lactation in this species significantly alters water and energy needs. We investigated leadership in tightly knit harems and loosely bonded herds of multiple harems. Harem females tended to have habitual roles in the initiation of harem movement. In herds, however, we found no consistent leaders among harems. At both levels of social organization, lactation was a key determinant of leadership. In harems, lactating females were more likely to initiate movement than nonlactating females. In turn, harems containing lactating females were more likely to lead herd movements. Thus, we conclude that social relationships and reproductive state together shape the interactions that produce group behaviours. One benefit to lactating females of leading herd movements is preferential access to scarce water. Thus, leadership roles in group decisions may have fitness consequences.  
  Address  
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  Notes Approved no  
  Call Number (up) Equine Behaviour @ team @ room B 3.092 Serial 1825  
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Author Rubenstein, D. I.; Hack, M. A. doi  openurl
  Title Horse signals: The sounds and scents of fury Type Journal Article
  Year 1992 Publication Evolutionary Ecology Abbreviated Journal Evol. Ecol.  
  Volume 6 Issue 3 Pages 254-260  
  Keywords ommunication – combat – fighting ability – individual identity – signals – information – assessment – displays  
  Abstract During contests animals typically exchange information about fighting ability. Among feral horses these signals involve olfactory or acoustical elements and each type can effectively terminate contests before physical contact becomes necessary. Dung transplant experiments show that for stallions, irrespective of rank, olfactory signals such as dung sniffing encode information about familiarity suggesting that such signals can be used as signatures. As such they can provide indirect information about fighting ability as long as opponents associate identity with past performance. Play-back experiments, however, show that vocalizations, such as squeals, directly provide information about status regardless of stallion familiarity. Sonographs reveal that squeals of dominants are longer than those of subordinates and that only those of dominants have at their onset high-frequency components.  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number (up) refbase @ user @ Serial 506  
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