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Author Krueger, K.; Flauger, B. url  doi
openurl 
  Title Social feeding decisions in horses (Equus caballus) Type Journal Article
  Year 2008 Publication Behavioural Processes Abbreviated Journal (up) Behav. Process.  
  Volume 78 Issue 1 Pages 76-83  
  Keywords Feeding decision; Horse; Rank; Social behaviour  
  Abstract Like many other herbivores, in a natural environment equids feed on rather evenly distributed resources. However, the vegetation in their vast habitats constantly changes. If food is plentiful only little competition occurs over food, and in non-competitive situations domestic horses tend to return to the same feeding site until it is overgrazed. In contrast, they compete over limited food for which the social status of the individuals appears to be important. Especially in ruminants several studies have proved an influence of social organisations, rank, sex and the depletion of feeding sites on the feeding behaviour of individuals. However, it is not yet understood whether and how social aspects affect horses“ feeding decisions. Curiosity about the influence of social rank on the horses” feeding decisions between two, equally with high-quality surplus food-filled buckets placed in different social feeding conditions, led us to create the test below. The observer horses were alternately tested with a dominant and a subordinate demonstrator placed in one of the three different positions. We conclude that domestic horses use social cognition and strategic decision making in order to decide where to feed in a social feeding situation. When possible they tend to return to the same, continuously supplied feeding site and switch to an “avoidance tendency” in the presence of dominant horses or when another horse is already feeding there. Thus, the social rank and the position of conspecifics affect the feeding strategy of horses.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 4394  
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Author Schloegl, C.; Kotrschal, K.; Bugnyar, T. url  doi
openurl 
  Title Modifying the object-choice task: Is the way you look important for ravens? Type Journal Article
  Year 2008 Publication Behavioural Processes Abbreviated Journal (up) Behav. Process.  
  Volume 77 Issue 1 Pages 61-65  
  Keywords Gaze; Modification; Object-choice task; Raven  
  Abstract Most animals seem to have difficulties in using gaze cues to find hidden food in object-choice tasks. For instance, chimpanzees usually fail in these tests, even though they are capable of following other's gaze geometrically behind barriers. Similar to chimpanzees, common ravens are skilled in tracking other's gaze but fail in object-choice tasks. We here explored whether procedural modifications, which had been used successfully in chimpanzees, would also yield positive results in ravens. In our modifications (a) the experimenter approached the cup while gazing at it, (b) the gaze cue was accompanied by a sound and (c) the experimenter could actually see the food while giving the gaze cue. Two out of seven birds performed above chance level in some of these conditions. However, we ascribe this improvement to the individuals' learning ability rather than to an understanding of the communicative nature of the task. This interpretation is further supported by results of a follow-up experiment suggesting that ravens may not rely on conspecifics' gaze cues for finding food caches in a natural foraging context. In sum, our results suggest that ravens may not transfer their gaze follow abilities to foraging situations involving hidden food.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 4505  
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Author Feh, C.; Munkhtuya, B. url  doi
openurl 
  Title Male infanticide and paternity analyses in a socially natural herd of Przewalski`s horses: Sexual selection? Type Journal Article
  Year 2008 Publication Behavioural Processes Abbreviated Journal (up) Behav. Process.  
  Volume 78 Issue 3 Pages 335-339  
  Keywords DNA paternity analysis; Human disturbance; Male infanticide; Przewalski's horse (Equus ferus przewalskii); Sexual selection  
  Abstract The sexual selection hypothesis explains infanticide by males in many mammals. In our 11-year study, we investigated this hypothesis in a herd of Przewalski's horses where we had witnessed infanticidal attacks. Infanticide was highly conditional and not simply linked to takeovers. Attacks occurred in only five of 39 cases following a takeover, and DNA paternity revealed that, although infanticidal stallions were not the genetic fathers in four cases out of five, stallions present at birth did not significantly attempt to kill unrelated foals. Infanticide did not reduce birth intervals; only in one case out of five was the infanticidal stallion, the father of the next foal; mothers whose foals were attacked subsequently avoided associating with infanticidal stallions. Therefore, evidence for the sexual selection hypothesis was weak. The “human disturbance” hypothesis received some support, as only zoo bred stallions which grew up in unnatural social groups attacked foals of mares which were pregnant during takeovers.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 4632  
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Author Jacobs, A.; Maumy, M.; Petit, O. url  doi
openurl 
  Title The influence of social organisation on leadership in brown lemurs (Eulemur fulvus fulvus) in a controlled environment Type Journal Article
  Year 2008 Publication Behavioural Processes Abbreviated Journal (up) Behav. Process.  
  Volume 79 Issue 2 Pages 111-113  
  Keywords Animals; *Decision Making; Dominance-Subordination; *Exploratory Behavior; Female; Group Structure; *Leadership; Lemur/*psychology; Male; Sex Factors; *Social Environment  
  Abstract Studies on leadership during group movements in several lemur species showed that females were responsible for the travelling choices concerning time and direction. Interestingly, in these species females are dominant over males. We investigated the influence of social organisation upon leadership processes by studying a lemur species in which social organisation is characterized by the absence of female dominance: the brown lemur (Eulemur fulvus fulvus). The study was conducted on a semi-free ranging group of 11 individuals and the analysis performed on 69 group movements showed that all the individuals could initiate a group movement. In 34 cases, the whole group moved. There was no significant difference in the number of start attempts or in the number of group members involved from one initiator to another. Moreover, there was no effect of sex or age of the initiator on the number of individuals following it or on the speed of the joining process. Therefore, the leadership observed is widely distributed to all group members. These results support the hypothesis of an influence of social organisation upon the decision-making processes but still remain to be studied in a more relevant ecological context.  
  Address IPHC-DEPE, Equipe d'ethologie des primates, UMR 7178, Centre National de la Recherche Scientifique-Universite Louis Pasteur and Centre de Primatologie, Strasbourg, France  
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  ISSN 0376-6357 ISBN Medium  
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  Notes PMID:18586413 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5127  
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Author Sueur, C.; Petit, O. url  doi
openurl 
  Title Shared or unshared consensus decision in macaques? Type Journal Article
  Year 2008 Publication Behavioural Processes Abbreviated Journal (up) Behav. Process.  
  Volume 78 Issue 1 Pages 84-92  
  Keywords Collective movement; Decision-making; Leadership; Social style  
  Abstract Members of a social group have to make collective decisions in order to synchronise their activities. In a shared consensus decision, all group members can take part in the decision whereas in an unshared consensus decision, one individual, usually a dominant member of the group, takes the decision for the rest of the group. It has been suggested that the type of decision-making of a species could be influenced by its social style. To investigate this further, we studied collective movements in two species with opposed social systems, the Tonkean macaque (Macaca tonkeana) and the rhesus macaque (Macaca mulatta). From our results, it appears that the decision to move is the result of the choices and actions of several individuals in both groups. However, this consensus decision involved nearly all group members in Tonkean macaques whereas dominant and old individuals took a prominent role in rhesus macaques. Thus, we suggest that Tonkean macaques display equally shared consensus decisions to move, whereas in the same context rhesus macaque exhibit partially shared consensus decisions. Such a difference in making a collective decision might be linked to the different social systems of the two studied species.  
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  ISSN 0376-6357 ISBN Medium  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5129  
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Author Blackmore, T.L.; Foster, T.M.; Sumpter, C.E.; Temple, W. url  doi
openurl 
  Title An investigation of colour discrimination with horses (Equus caballus) Type Journal Article
  Year 2008 Publication Behavioural Processes Abbreviated Journal (up) Behav. Process.  
  Volume 78 Issue 3 Pages 387-396  
  Keywords Chromatic discrimination; Colour vision; Horse; Operant  
  Abstract The ability of four horses (Equus caballus) to discriminate coloured (three shades of blue, green, red, and yellow) from grey (neutral density) stimuli, produced by back projected lighting filters, was investigated in a two response forced-choice procedure. Pushes of the lever in front of a coloured screen were occasionally reinforced, pushes of the lever in front of a grey screen were never reinforced. Each colour shade was randomly paired with a grey that was brighter, one that was dimmer, and one that approximately matched the colour in terms of brightness. Each horse experienced the colours in a different order, a new colour was started after 85% correct responses over five consecutive sessions or if accuracy showed no trend over sessions. All horses reached the 85% correct with blue versus grey, three horses did so with both yellow and green versus grey. All were above chance with red versus grey but none reached criterion. Further analysis showed the wavelengths of the green stimuli used overlapped with the yellow. The results are consistent with histological and behavioural studies that suggest that horses are dichromatic. They differ from some earlier data in that they indicate horses can discriminate yellow and blue, but that they may have deficiencies in discriminating red and green.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5336  
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Author Bates, L.A.; Sayialel, K.N.; Njiraini, N.W.; Poole, J.H.; Moss, C.J.; Byrne, R.W. doi  openurl
  Title African elephants have expectations about the locations of out-of-sight family members Type Journal Article
  Year 2008 Publication Biology Letters Abbreviated Journal (up) Biol Lett  
  Volume 4 Issue 1 Pages 34-36  
  Keywords elephants, olfaction, urine, individual recognition  
  Abstract Monitoring the location of conspecifics may be important to social mammals. Here, we use an expectancy-violation paradigm to test the ability of African elephants (Loxodonta africana) to keep track of their social companions from olfactory cues. We presented elephants with samples of earth mixed with urine from female conspecifics that were either kin or unrelated to them, and either unexpected or highly predictable at that location. From behavioural measurements of the elephants' reactions, we show that African elephants can recognize up to 17 females and possibly up to 30 family members from cues present in the urine-earth mix, and that they keep track of the location of these individuals in relation to themselves.  
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  Notes Approved yes  
  Call Number Equine Behaviour @ team @ Serial 4332  
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Author Berge, J.; Cottier, F.; Last, K.S.; Varpe, O.; Leu, E.; Soreide, J.; Eiane, K.; Falk-Petersen, S.; Willis, K.; Nygard, H.; Vogedes, D.; Griffiths, C.; Johnsen, G.; Lorentzen, D.; Brierley, A.S. url  doi
openurl 
  Title Diel vertical migration of Arctic zooplankton during the polar night Type Journal Article
  Year 2008 Publication Biology Letters Abbreviated Journal (up) Biol Lett  
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  Abstract High-latitude environments show extreme seasonal variation in physical and biological variables. The classic paradigm of Arctic marine ecosystems holds that most biological processes slow down or cease during the polar night. One key process that is generally assumed to cease during winter is diel vertical migration (DVM) of zooplankton. DVM constitutes the largest synchronized movement of biomass on the planet, and is of paramount importance for marine ecosystem function and carbon cycling. Here we present acoustic data that demonstrate a synchronized DVM behaviour of zooplankton that continues throughout the Arctic winter, in both open and ice-covered waters. We argue that even during the polar night, DVM is regulated by diel variations in solar and lunar illumination, which are at intensities far below the threshold of human perception. We also demonstrate that winter DVM is stronger in open waters compared with ice-covered waters. This suggests that the biologically mediated vertical flux of carbon will increase if there is a continued retreat of the Arctic winter sea ice cover.  
  Address University Centre in Svalbard, Pb 156, 9171 Longyearbyen, Norway The Scottish Association for Marine Science, Dunstaffnage Marine Laboratories, Oban, Argyll PA37 1QA, UK  
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  ISSN 1744-9561 ISBN Medium  
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  Notes PMID:18948249 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4629  
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Author Rands, S.A.; Cowlishaw, G.; Pettifor, R.A.; Rowcliffe, J.M.; Johnstone, R.A. url  doi
openurl 
  Title The emergence of leaders and followers in foraging pairs when the qualities of individuals differ Type Journal Article
  Year 2008 Publication BMC Evolutionary Biology Abbreviated Journal (up) BMC Evol Biol  
  Volume 8 Issue Pages 51  
  Keywords Animals; *Feeding Behavior; *Food Chain; *Models, Biological; *Social Dominance  
  Abstract BACKGROUND: Foraging in groups offers animals a number of advantages, such as increasing their likelihood of finding food or detecting and avoiding predators. In order for a group to remain together, there has to be some degree of coordination of behaviour and movement between its members (which may in some cases be initiated by a decision-making leader, and in other cases may emerge as an underlying property of the group). For example, behavioural synchronisation is a phenomenon where animals within a group initiate and then continue to conduct identical behaviours, and has been characterised for a wide range of species. We examine how a pair of animals should behave using a state-dependent approach, and ask what conditions are likely to lead to behavioural synchronisation occurring, and whether one of the individuals is more likely to act as a leader. RESULTS: The model we describe considers how the energetic gain, metabolic requirements and predation risks faced by the individuals affect measures of their energetic state and behaviour (such as the degree of behavioural synchronisation seen within the pair, and the value to an individual of knowing the energetic state of its colleague). We explore how predictable changes in these measures are in response to changes in physiological requirements and predation risk. We also consider how these measures should change when the members of the pair are not identical in their metabolic requirements or their susceptibility to predation. We find that many of the changes seen in these measures are complex, especially when asymmetries exist between the members of the pair. CONCLUSION: Analyses are presented that demonstrate that, although these general patterns are robust, care needs to be taken when considering the effects of individual differences, as the relationship between individual differences and the resulting qualitative changes in behaviour may be complex. We discuss how these results are related to experimental observations, and how the model and its predictions could be extended.  
  Address Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. sean.rands@bristol.ac.uk  
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  Series Volume Series Issue Edition  
  ISSN 1471-2148 ISBN Medium  
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  Notes PMID:18282297 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5126  
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Author King, A.J.; Douglas, C.M.S.; Huchard, E.; Isaac, N.J.B.; Cowlishaw, G. url  doi
openurl 
  Title Dominance and affiliation mediate despotism in a social primate Type Journal Article
  Year 2008 Publication Current Biology : CB Abbreviated Journal (up) Curr Biol  
  Volume 18 Issue 23 Pages 1833-1838  
  Keywords Animals; *Authoritarianism; Behavior, Animal/*physiology; Cooperative Behavior; *Decision Making; Feeding Behavior; Female; *Group Processes; Male; Papio ursinus/*psychology; *Social Dominance  
  Abstract Group-living animals routinely have to reach a consensus decision and choose between mutually exclusive actions in order to coordinate their activities and benefit from sociality. Theoretical models predict “democratic” rather than “despotic” decisions to be widespread in social vertebrates, because they result in lower “consensus costs”-the costs of an individual foregoing its optimal action to comply with the decision-for the group as a whole. Yet, quantification of consensus costs is entirely lacking, and empirical observations provide strong support for the occurrence of both democratic and despotic decisions in nature. We conducted a foraging experiment on a wild social primate (chacma baboons, Papio ursinus) in order to gain new insights into despotic group decision making. The results show that group foraging decisions were consistently led by the individual who acquired the greatest benefits from those decisions, namely the dominant male. Subordinate group members followed the leader despite considerable consensus costs. Follower behavior was mediated by social ties to the leader, and where these ties were weaker, group fission was more likely to occur. Our findings highlight the importance of leader incentives and social relationships in group decision-making processes and the emergence of despotism.  
  Address Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK. andrew.king@ioz.ac.uk  
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  ISSN 0960-9822 ISBN Medium  
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  Notes PMID:19026539 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5124  
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