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Author Massen, J.; Sterck, E.; de Vos, H. url  openurl
  Title Close social associations in animals and humans: functions and mechanisms of friendship Type
  Year 2010 Publication Behaviour Abbreviated Journal  
  Volume 147 Issue 11 Pages (down) 1379  
  Keywords Both humans and group-living animals associate and behave affiliatively more with some individuals than others. Human friendship has long been acknowledged, and recently scientists studying animal behaviour have started using the term friendship for close social associates in animals. Yet, while biologists describe friends as social tools to enhance fitness, social scientists describe human friendship as unconditional. We investigate whether these different descriptions reflect true differences in human friendship and animal close social associations or are a by-product of different research approaches: namely social scientists focussing on proximate and biologists on ultimate explanations. We first stress the importance of similar measures to determine close social associations, thereafter examine their ultimate benefits and proximate motivations, and discuss the latest findings on the central-neural regulation of social bonds. We conclude that both human friendship and animal close social associations are ultimately beneficial. On the proximate level, motivations for friendship in humans and for close social associations in animals are not necessarily based on benefits and are often unconditional. Moreover, humans share with many animals a similar physiological basis of sociality. Therefore, biologists and social scientist describe the same phenomenon, and the use of the term friendship for animals seems justified.  
  Abstract Both humans and group-living animals associate and behave affiliatively more with some individuals than others. Human friendship has long been acknowledged, and recently scientists studying animal behaviour have started using the term friendship for close social associates in animals. Yet, while biologists describe friends as social tools to enhance fitness, social scientists describe human friendship as unconditional. We investigate whether these different descriptions reflect true differences in human friendship and animal close social associations or are a by-product of different research approaches: namely social scientists focussing on proximate and biologists on ultimate explanations. We first stress the importance of similar measures to determine close social associations, thereafter examine their ultimate benefits and proximate motivations, and discuss the latest findings on the central-neural regulation of social bonds. We conclude that both human friendship and animal close social associations are ultimately beneficial. On the proximate level, motivations for friendship in humans and for close social associations in animals are not necessarily based on benefits and are often unconditional. Moreover, humans share with many animals a similar physiological basis of sociality. Therefore, biologists and social scientist describe the same phenomenon, and the use of the term friendship for animals seems justified.  
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  Call Number Equine Behaviour @ team @ Serial 5813  
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Author Lusseau, D.; Conradt, L. url  doi
openurl 
  Title The emergence of unshared consensus decisions in bottlenose dolphins Type Journal Article
  Year 2009 Publication Behavioral Ecology and Sociobiology Abbreviated Journal Behav. Ecol. Sociobiol.  
  Volume 63 Issue 7 Pages (down) 1067-1077  
  Keywords Behavioral ecology – Decision-making process – Bottlenose dolphin – Group living  
  Abstract Abstract  Unshared consensus decision-making processes, in which one or a small number of individuals make the decision for the rest of a group, are rarely documented. However, this mechanism can be beneficial for all group members when one individual has greater knowledge about the benefits of the decision than other group members. Such decisions are reached during certain activity shifts within the population of bottlenose dolphins residing in Doubtful Sound, New Zealand. Behavioral signals are performed by one individual and seem to precipitate shifts in the behavior of the entire group: males perform side flops and initiate traveling bouts while females perform upside-down lobtails and terminate traveling bouts. However, these signals are not observed at all activity shifts. We find that, while side flops were performed by males that have greater knowledge than other male group members, this was not the case for females performing upside-down lobtails. The reason for this could have been that a generally high knowledge about the optimal timing of travel terminations rendered it less important which individual female made the decision.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5109  
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Author Knopff, K.; Pavelka, M. doi  openurl
  Title Feeding Competition and Group Size in Alouatta pigra Type Journal Article
  Year 2006 Publication International Journal of Primatology Abbreviated Journal Int. J. Primatol.  
  Volume 27 Issue 4 Pages (down) 1059-1078  
  Keywords Alouatta pigra – ecological constraints – group size – infanticide – social constraints  
  Abstract Researchers consider group size in primates to be determined by complex relationships among numerous ecological forces. Antipredator benefits and better resource defense are the primary pressures for large groups. Conversely, intragroup limited food availability, can result in greater intragroup feeding competition and individual energy expenditure in larger groups, creating energetic advantages for individuals in small groups and placing an upper limit group size. However, the extent to which food availability constrains group size remains unclear for many species, including black howlers (Alouatta pigra), which ubiquitously live in small social groups (≤10 individuals). We studied the relationship between group size and 2 key indices of feeding competition-day journey length and activity budgets in 3 groups of wild Alouatta pigra at a hurricane-damaged site in Belize, Central America. We controlled for differences in food availability between home ranges (food tree density) and compared both indicators of feeding competition directly with temporal variation in food availability for each group. Our results show no consistent association between resource availability, group size, and either index of competition, indicating that feeding competition does not limit group size at the site i.e., that larger groups can form without increased costs of feeding competition. The results support the search for other explanations, possibly social ones, for small group size in the primates, and we conclude with suggestions and evidence for such alternative explanations.  
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  Call Number refbase @ user @ Serial 808  
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Author Sárová, R.; Spinka, M.; Panamá, J.L.A.; Simecek, P. url  doi
openurl 
  Title Graded leadership by dominant animals in a herd of female beef cattle on pasture Type Journal Article
  Year 2010 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.  
  Volume 79 Issue 5 Pages (down) 1037-1045  
  Keywords Bos taurus; cattle; dominance; foraging; Gps; group movement; leadership  
  Abstract The role of dominant individuals in leading groups of animals is not yet well understood. We investigated whether dominant beef cows, Bos taurus, have more influence on herd movement on pasture than more subordinate cows. A herd of 15 Gasconne cows was observed for a 3-week period between dawn and dusk. The positions of all adult cows were recorded with GPS collars at 1 min intervals and the behaviour of each cow was recorded in 5 min scans. The dominance hierarchy was recorded by ad libitum sampling. Through cluster analysis of the recorded data, we distinguished three herd behaviour patterns: resting, foraging and travelling. Dominant cows were closer to the front of the herd during both travelling and foraging. During travelling, more dominant cows also had more direct trajectories and were more aligned both with their nearest neighbours and with the whole herd. During foraging, the trajectories of dominant cows were shorter than those of subordinate cows. The results indicate that foraging and short-distance travelling movements by female beef cattle are not led by any particular individual but rather are influenced by a graded type of leadership; that is, the more dominant a cow is, the stronger the influence it may have on the movements of the herd.  
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  ISSN 0003-3472 ISBN Medium  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5271  
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Author Hagen, S.J.; Eaton, W.A. doi  openurl
  Title Two-state expansion and collapse of a polypeptide Type Journal Article
  Year 2000 Publication Journal of Molecular Biology Abbreviated Journal J Mol Biol  
  Volume 301 Issue 4 Pages (down) 1019-1027  
  Keywords Animals; Computer Simulation; Cytochrome c Group/*chemistry/*metabolism; Horses; Kinetics; Lasers; Models, Chemical; Peptides/*chemistry/*metabolism; Protein Conformation; Protein Denaturation; *Protein Folding; Spectrometry, Fluorescence; Temperature; Thermodynamics  
  Abstract The initial phase of folding for many proteins is presumed to be the collapse of the polypeptide chain from expanded to compact, but still denatured, conformations. Theory and simulations suggest that this collapse may be a two-state transition, characterized by barrier-crossing kinetics, while the collapse of homopolymers is continuous and multi-phasic. We have used a laser temperature-jump with fluorescence spectroscopy to measure the complete time-course of the collapse of denatured cytochrome c with nanosecond time resolution. We find the process to be exponential in time and thermally activated, with an apparent activation energy approximately 9 k(B)T (after correction for solvent viscosity). These results indicate that polypeptide collapse is kinetically a two-state transition. Because of the observed free energy barrier, the time scale of polypeptide collapse is dramatically slower than is predicted by Langevin models for homopolymer collapse.  
  Address Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Building 5, Bethesda, MD, 20892-0520, USA  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-2836 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:10966803 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3790  
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Author Keiper, R.; Houpt, K. openurl 
  Title Reproduction in feral horses: an eight-year study Type Journal Article
  Year 1984 Publication American journal of veterinary research Abbreviated Journal Am J Vet Res  
  Volume 45 Issue 5 Pages (down) 991-995  
  Keywords Abortion, Veterinary/epidemiology; Anestrus; Animal Population Groups/*physiology; Animals; Animals, Wild/*physiology; Birth Rate; Female; Fertility; Horse Diseases/epidemiology; Horses/*physiology; Lactation; Male; Maryland; Pregnancy; *Reproduction; Seasons; Sex Ratio; Virginia  
  Abstract The reproductive rate and foal survival of the free-ranging ponies on Assateague Island National Seashore were studied for 8 years, 1975 to 1982. Most (52%) of the 86 foals were born in May, 13% were born in April, 22.6% in June, 10.4% in July, and less than 1% in August and September. The mean foaling rate was 57.1 +/- 3.9% and the survival rate was 88.3 +/- 3.6%. Forty-eight colts and 55 fillies were born (sex ratio 53% female). Mares less than 3 years old did not foal and the foaling rate of 3-year-old mares was only 23%, that of 4-year-old mares was 46%, that of 5-year-old mares was 53%, and 6-year-old mares was 69%. The relatively poor reproduction rate was believed to be a consequence of the stress of lactating while carrying a foal when forage quality on the island was low. The hypothesis was supported by the higher reproductive rate (74.4 +/- 2.4%) of the ponies in the Chincoteague National Wildlife Refuge on the southern part of the island. Their foals are weaned and sold in July each year. Despite the low reproductive rate on Assateague Island National Seashore , the number of ponies increased from 43 to 80, a 90% increase in the 8-year period or greater than 10%/yr. There were 24 deaths and 8 dispersals from the study area.  
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  ISSN 0002-9645 ISBN Medium  
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  Notes PMID:6732036 Approved no  
  Call Number refbase @ user @ Serial 665  
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Author Pierce, M.M.; Nall, B.T. doi  openurl
  Title Coupled kinetic traps in cytochrome c folding: His-heme misligation and proline isomerization Type Journal Article
  Year 2000 Publication Journal of Molecular Biology Abbreviated Journal J Mol Biol  
  Volume 298 Issue 5 Pages (down) 955-969  
  Keywords Amino Acid Sequence; Amino Acid Substitution/genetics; Binding Sites; Cytochrome c Group/*chemistry/genetics/*metabolism; *Cytochromes c; Enzyme Stability/drug effects; Fluorescence; Guanidine/pharmacology; Heme/*metabolism; Histidine/genetics/*metabolism; Hydrogen-Ion Concentration; Isomerism; Kinetics; Models, Molecular; Molecular Sequence Data; Mutation/genetics; Proline/*chemistry/metabolism; Protein Conformation/drug effects; Protein Denaturation/drug effects; *Protein Folding; Protein Renaturation; Saccharomyces cerevisiae/enzymology/genetics; Sequence Alignment; Thermodynamics  
  Abstract The effect of His-heme misligation on folding has been investigated for a triple mutant of yeast iso-2 cytochrome c (N26H,H33N,H39K iso-2). The variant contains a single misligating His residue at position 26, a location at which His residues are found in several cytochrome c homologues, including horse, tuna, and yeast iso-1. The amplitude for fast phase folding exhibits a strong initial pH dependence. For GdnHCl unfolded protein at an initial pH<5, the observed refolding at final pH 6 is dominated by a fast phase (tau(2f)=20 ms, alpha(2f)=90 %) that represents folding in the absence of misligation. For unfolded protein at initial pH 6, folding at final pH 6 occurs in a fast phase of reduced amplitude (alpha(2f) approximately 20 %) but the same rate (tau(2f)=20 ms), and in two slower phases (tau(m)=6-8 seconds, alpha(m) approximately 45 %; and tau(1b)=16-20 seconds, alpha(1b) approximately 35 %). Double jump experiments show that the initial pH dependence of the folding amplitudes results from a slow pH-dependent equilibrium between fast and slow folding species present in the unfolded protein. The slow equilibrium arises from coupling of the His protonation equilibrium to His-heme misligation and proline isomerization. Specifically, Pro25 is predominantly in trans in the unligated low-pH unfolded protein, but is constrained in a non-native cis isomerization state by His26-heme misligation near neutral pH. Refolding from the misligated unfolded form proceeds slowly due to the large energetic barrier required for proline isomerization and displacement of the misligated His26-heme ligand.  
  Address Center for Biomolecular Structure, Department of Biochemistry, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA  
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  Series Volume Series Issue Edition  
  ISSN 0022-2836 ISBN Medium  
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  Notes PMID:10801361 Approved no  
  Call Number refbase @ user @ Serial 3853  
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Author Faria, J.J.; Dyer, J.R.G.; Tosh, C.R.; Krause, J. url  doi
openurl 
  Title Leadership and social information use in human crowds Type Journal Article
  Year 2010 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.  
  Volume 79 Issue 4 Pages (down) 895-901  
  Keywords collective animal behaviour; group; human; inadvertent social cue; information; leadership  
  Abstract One of the big challenges for group-living animals is to find out who in a group has pertinent information (regarding food or predators) at any moment in time, because informed individuals may not be obviously recognizable to other group members. We found that individuals in human groups were capable of identifying those with information, and this identification increased group performance: the speed and accuracy of groups in reaching a target. Using video analysis we found how informed individuals might have been identified by other group members by means of inadvertent social cues (such as starting order, time spent following and group position). Furthermore, we were able to show that at least one of these cues, the group position of informed individuals, was indeed correlated with group performance. Our final experiment confirmed that leadership was even more efficient when the group members were given the identity of the leader. We discuss the effect of information status regarding the presence and identity of leaders on collective animal behaviour.  
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  ISSN 0003-3472 ISBN Medium  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5192  
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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 (down) 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.  
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  Call Number Equine Behaviour @ team @ room B 3.092 Serial 1825  
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Author Dyer, J.R.G.; Johansson, A.; Helbing, D.; Couzin, I.D.; Krause, J. url  doi
openurl 
  Title Leadership, consensus decision making and collective behaviour in humans Type Journal Article
  Year 2009 Publication Philosophical Transactions of the Royal Society B: Biological Sciences Abbreviated Journal Phil. Trans. Biol. Sci.  
  Volume 364 Issue 1518 Pages (down) 781-789  
  Keywords * leadership * consensus decision making * collective behaviour * human group  
  Abstract This paper reviews the literature on leadership in vertebrate groups, including recent work on human groups, before presenting the results of three new experiments looking at leadership and decision making in small and large human groups. In experiment 1, we find that both group size and the presence of uninformed individuals can affect the speed with which small human groups (eight people) decide between two opposing directional preferences and the likelihood of the group splitting. In experiment 2, we show that the spatial positioning of informed individuals within small human groups (10 people) can affect the speed and accuracy of group motion. We find that having a mixture of leaders positioned in the centre and on the edge of a group increases the speed and accuracy with which the group reaches their target. In experiment 3, we use large human crowds (100 and 200 people) to demonstrate that the trends observed from earlier work using small human groups can be applied to larger crowds. We find that only a small minority of informed individuals is needed to guide a large uninformed group. These studies build upon important theoretical and empirical work on leadership and decision making in animal groups.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5122  
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