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Author Conradt, L.; Roper, T.J. url  doi
openurl 
  Title Group decision-making in animals Type Journal Article
  Year 2003 Publication Nature Abbreviated Journal Nature  
  Volume 421 Issue 6919 Pages 155-158  
  Keywords Animals; Behavior, Animal/*physiology; *Decision Making; Democracy; Group Processes; *Models, Biological; Population Density; Social Behavior  
  Abstract Groups of animals often need to make communal decisions, for example about which activities to perform, when to perform them and which direction to travel in; however, little is known about how they do so. Here, we model the fitness consequences of two possible decision-making mechanisms: 'despotism' and 'democracy'. We show that under most conditions, the costs to subordinate group members, and to the group as a whole, are considerably higher for despotic than for democratic decisions. Even when the despot is the most experienced group member, it only pays other members to accept its decision when group size is small and the difference in information is large. Democratic decisions are more beneficial primarily because they tend to produce less extreme decisions, rather than because each individual has an influence on the decision per se. Our model suggests that democracy should be widespread and makes quantitative, testable predictions about group decision-making in non-humans.  
  Address School of Biological Sciences, University of Sussex, Brighton BN1 9QG, UK. l.conradt@sussex.ac.uk  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language (down) English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0028-0836 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:12520299 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5136  
Permanent link to this record
 
 
Author Rands, S.A.; Cowlishaw, G.; Pettifor, R.A.; Rowcliffe, J.M.; Johnstone, R.A. url  doi
openurl 
  Title Spontaneous emergence of leaders and followers in foraging pairs Type Journal Article
  Year 2003 Publication Nature Abbreviated Journal Nature  
  Volume 423 Issue 6938 Pages 432-434  
  Keywords Animals; *Energy Metabolism; Food; *Food Chain; *Models, Biological; Motor Activity; *Social Behavior; Time Factors  
  Abstract Animals that forage socially often stand to gain from coordination of their behaviour. Yet it is not known how group members reach a consensus on the timing of foraging bouts. Here we demonstrate a simple process by which this may occur. We develop a state-dependent, dynamic game model of foraging by a pair of animals, in which each individual chooses between resting or foraging during a series of consecutive periods, so as to maximize its own individual chances of survival. We find that, if there is an advantage to foraging together, the equilibrium behaviour of both individuals becomes highly synchronized. As a result of this synchronization, differences in the energetic reserves of the two players spontaneously develop, leading them to adopt different behavioural roles. The individual with lower reserves emerges as the 'pace-maker' who determines when the pair should forage, providing a straightforward resolution to the problem of group coordination. Moreover, the strategy that gives rise to this behaviour can be implemented by a simple 'rule of thumb' that requires no detailed knowledge of the state of other individuals.  
  Address Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. s.rands@zoo.cam.ac.uk  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language (down) English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0028-0836 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:12761547 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5138  
Permanent link to this record
 
 
Author Newman, M.E.J. url  doi
openurl 
  Title Mixing patterns in networks Type Journal Article
  Year 2003 Publication Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics Abbreviated Journal Phys Rev E Stat Nonlin Soft Matter Phys  
  Volume 67 Issue 2 Pt 2 Pages 026126  
  Keywords  
  Abstract We study assortative mixing in networks, the tendency for vertices in networks to be connected to other vertices that are like (or unlike) them in some way. We consider mixing according to discrete characteristics such as language or race in social networks and scalar characteristics such as age. As a special example of the latter we consider mixing according to vertex degree, i.e., according to the number of connections vertices have to other vertices: do gregarious people tend to associate with other gregarious people? We propose a number of measures of assortative mixing appropriate to the various mixing types, and apply them to a variety of real-world networks, showing that assortative mixing is a pervasive phenomenon found in many networks. We also propose several models of assortatively mixed networks, both analytic ones based on generating function methods, and numerical ones based on Monte Carlo graph generation techniques. We use these models to probe the properties of networks as their level of assortativity is varied. In the particular case of mixing by degree, we find strong variation with assortativity in the connectivity of the network and in the resilience of the network to the removal of vertices.  
  Address Department of Physics, University of Michigan, Ann Arbor, MI 48109-1120, USA  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language (down) English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1539-3755 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:12636767 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5215  
Permanent link to this record
 
 
Author Lee, R.D. doi  openurl
  Title Rethinking the evolutionary theory of aging: transfers, not births, shape senescence in social species Type Journal Article
  Year 2003 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc Natl Acad Sci U S A  
  Volume 100 Issue 16 Pages 9637-9642  
  Keywords Adaptation, Physiological; *Aging; Animals; *Biological Evolution; Demography; Economics; Environment; Fertility; Humans; Life Expectancy; Longevity; Models, Theoretical; Parturition; Population Dynamics; Population Growth; Reproduction  
  Abstract The classic evolutionary theory of aging explains why mortality rises with age: as individuals grow older, less lifetime fertility remains, so continued survival contributes less to reproductive fitness. However, successful reproduction often involves intergenerational transfers as well as fertility. In the formal theory offered here, age-specific selective pressure on mortality depends on a weighted average of remaining fertility (the classic effect) and remaining intergenerational transfers to be made to others. For species at the optimal quantity-investment tradeoff for offspring, only the transfer effect shapes mortality, explaining postreproductive survival and why juvenile mortality declines with age. It also explains the evolution of lower fertility, longer life, and increased investments in offspring.  
  Address Department of Demography, University of California, 2232 Piedmont Avenue, Berkeley, CA 94720-2120, USA. rlee@demog.berkeley.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language (down) English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0027-8424 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:12878733 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5465  
Permanent link to this record
 
 
Author Lefebvre, L.; Bouchard, J. isbn  openurl
  Title Social learning about food in birds Type Book Chapter
  Year 2003 Publication The Biology of Traditions Abbreviated Journal  
  Volume Issue Pages 94-126  
  Keywords  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Cambridge University Press Place of Publication Cambridge Editor Fragaszy, D.M; Perry, S.  
  Language (down) Englisch Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN 978-0521815970 Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5471  
Permanent link to this record
 
 
Author Westerduin, F.E.; Lankveld, D.P.K.; van der Velden, M.A.; Back, W.; Sloet van Oldruitenborgh-Oosterbaan, M.M. openurl 
  Title [Splenectomy in a dressage pony: end of sports career?] Type Journal Article
  Year 2003 Publication Tijdschrift Voor Diergeneeskunde Abbreviated Journal Tijdschr Diergeneeskd  
  Volume 128 Issue 13 Pages 406-411  
  Keywords Animals; Biopsy/veterinary; Colic/surgery/veterinary; Horse Diseases/pathology/*surgery/ultrasonography; Horses; Laparotomy/veterinary; Male; Splenectomy/*veterinary; Splenomegaly/surgery/ultrasonography/*veterinary; *Sports  
  Abstract A 14-year-old Arabian cross-bred gelding was referred to the University Clinic because of mild, recurrent signs of colic for 5 days. The pony showed icteric mucous membranes, haemolytic blood, and dark coloured urine. Internal examination did not give a clear diagnosis. Unidentified intra-abdominal strands were found and haemorrhagic abdominocentesis led to the decision to perform an exploratory laparatomy. An extremely enlarged spleen was the sole finding. A splenal biopsy sample was taken and surgery was completed. The pony remained colicky, so the spleen was examined by ultrasonography. After this examination, the tentative diagnosis 'tumour of the spleen' was made and splenectomy was performed. Pathological examination of the spleen revealed splenomegaly caused by infarctions of unknown origin. Eight weeks after surgery, the pony started again in dressage competition. Six months after splenectomy, the pony won the provincial dressage competition.  
  Address Hoofdafdeling Gezondheidszorg Paard, Faculteit der Diergeneeskunde, Universiteit Utrecht, Yalelaan 12-16, 3584 CM Utrecht. fenna-lambert@planet.nl  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language (down) Dutch Summary Language Original Title Splenectomie bij een dressuurpony: einde sportcarriere?  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0040-7453 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:12870176 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3722  
Permanent link to this record
 
 
Author Huebener, E. (ed) url  openurl
  Title Fortschritt des Wissens zu Grundsitz und Schenkelhilfen und die “Entdeckung” der Bewegungen des Pferderückens und des Pferderumpfes Type Manuscript
  Year 2003 Publication www.reiten-lesen-denken.de Abbreviated Journal  
  Volume Issue Pages 6  
  Keywords Grundsitz – Stehsitz – Unterschenkel-Vorstreck-Sitz – Balancesitz – Erkenntnisse seit Erfindung des Buchdrucks – vom 16. bis 20.Jh.  
  Abstract Tabellarische, chronologische übersicht zur Entwicklung des Grundsitzes durch fünf Jahrhunderte, wobei “Grundsitz” als Oberbegriff für verschiedene Formen des wirklich sitzenden “Hoch zu Roß” dient. Fehlentwicklungen (anstatt von Fortschritten, nur in Ausnahmefällen erwähnt)sind fett kursiv als solche gekennzeichnet.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor Huebener, E.  
  Language (down) Deutsch Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium Web Site  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Reiten Lesen Denken @ eberhardhuebener @ Serial 1762  
Permanent link to this record
 
 
Author Huebener, E. openurl 
  Title Basis Seat and Leg Aids – Evolution of Knowledge Type Manuscript
  Year 2003 Publication www.reiten-lesen-denken.de Abbreviated Journal  
  Volume Issue Pages 6  
  Keywords  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language (down) Deutsch Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium Web Site  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Reiten Lesen Denken @ eberhardhuebener @ Serial 1763  
Permanent link to this record
 
 
Author Sondergaard, E.; Halekoh, U. url  openurl
  Title Young horses' reactions to humans in relation to handling and social environment Type Journal Article
  Year 2003 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.  
  Volume 84 Issue 4 Pages 265-280  
  Keywords Horses; Human-animal relationship; Social environment; Handling  
  Abstract Forty Danish warmblood colts in two replicates were used to investigate the effect of housing and handling in the rearing period on the reactions to humans. The horses entered the experiment after weaning and were housed either individually (n=16) or in groups of three (n=24). Half of the horses from each housing group were handled three times per week for a period of 10 min. Approach tests were performed in the home environment when the horses were 6, 9, 12, 18, 21, and 24 months old, and an Arena and Human Encounter test was performed in a novel environment when the horses were 12 and 24 months old, respectively. In the home environment, single-housed horses approached sooner and were more easily approached by a human than group-housed horses where no effect of handling was observed. Horses approached sooner and were more easily approached with increasing age. In the Arena and Human Encounter test, single-housed horses expressed less restless behaviour, more explorative behaviour, and less vocalisation than group-housed horses. Handled horses showed lower increase in heart rate during the test than non-handled horses. There was no difference between the number of times single or group-housed horses touched an unfamiliar person in the Arena and Human Encounter test but handled horses approached sooner than non-handled horses. It is concluded that the social environment affected the way horses reacted to humans when tested in the home environment but not in a novel environment. In contrast, handling affected the reactions to humans when tested in the novel environment but not in the home environment. However, handled horses also reacted less to the novel environment in general, thus indicating that handling is a mean of avoiding potential dangerous situations.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language (down) Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number refbase @ user @ Serial 308  
Permanent link to this record
 
 
Author Visser, E.K.; Van Reenen, C.G.; Engel, B.; Schilder, M.B.H.; Barneveld, A.; Blokhuis, H.J. doi  openurl
  Title The association between performance in show-jumping and personality traits earlier in life Type Journal Article
  Year 2003 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.  
  Volume 82 Issue 4 Pages 279-295  
  Keywords Personality; Performance; Horses; Prediction; Individual differences; Behavioural tests  
  Abstract For a horse to succeed in a show-jumping career, the individual has to possess both excellent physical abilities as well as a suitable personality to perform under challenging conditions. Forty-one Dutch Warmblood horses were used to develop personality tests and correlations between test variables and early training performances in jumping were studied. In behavioural tests, during the first 2 years of the horses' lives, personality aspects like emotionality, reactivity to human and learning abilities were quantified. At the age of 3, horses were broken and received early training in show-jumping. The inter-relationship between several performance variables measured during this early training phase were studied using principal component analysis (PCA). Variables measured in the different personality tests (novel-object test, handling test, avoidance-learning test and a reward-learning test) showed no correlations, suggesting that these tests all triggered different aspects of a horse's personality. This study indicates that it is possible to predict a substantial part of the show-jumping performance of an individual horse later in life by personality traits earlier in life.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language (down) Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number refbase @ user @ Serial 326  
Permanent link to this record
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