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Author Wich, S.A.; de Vries, H. doi  openurl
  Title Male monkeys remember which group members have given alarm calls Type Journal Article
  Year 2006 Publication (down) Proceedings. Biological Sciences / The Royal Society Abbreviated Journal Proc Biol Sci  
  Volume 273 Issue 1587 Pages 735-740  
  Keywords Animals; Behavior, Animal/*physiology; Cercopithecidae/*physiology/*psychology; Cognition/physiology; Fear/physiology/*psychology; Female; Indonesia; Male; Vocalization, Animal/*physiology  
  Abstract Primates give alarm calls in response to the presence of predators. In some species, such as the Thomas langur (Presbytis thomasi), males only emit alarm calls if there is an audience. An unanswered question is whether the audience's behaviour influences how long the male will continue his alarm calling. We tested three hypotheses that might explain the alarm calling duration of male Thomas langurs: the fatigue, group size and group member behaviour hypotheses. Fatigue and group size did not influence male alarm calling duration. We found that males only ceased calling shortly after all individuals in his group had given at least one alarm call. This shows that males keep track of and thus remember which group members have called.  
  Address Behavioural Biology, Utrecht University, Padualaan 14, 3584 Utrecht, The Netherlands. s.a.wich@bio.uu.nl  
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  Series Volume Series Issue Edition  
  ISSN 0962-8452 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16608694 Approved no  
  Call Number Equine Behaviour @ team @ Serial 2816  
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Author Reeve, H. Kern url  doi
openurl 
  Title Evolutionarily stable communication between kin: a general model Type Journal Article
  Year 1997 Publication (down) Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. Roy. Soc. Lond. B Biol. Sci.  
  Volume 264 Issue (1384) Pages 1037-1040.  
  Keywords Signalling Systems  
  Abstract At present, the most general evolutionary theory of honest communication is Grafen's model of Zahavi's 'handicap' signalling system, in which honesty of signals about the signaller's quality (e.g. mate suitability or fighting ability) is maintained by the differentially high cost of signals to signallers having lower quality. The latter model is here further generalized to include any communication between signallers and receivers that are genetically related (e.g. parents and begging offspring, cooperative or competing siblings). Signalling systems involving relatives are shown to be evolutionarily stable, despite a potential pay-off for false signalling, if the Zahavian assumption of differential signal costs holds and there are diminishing reproductive returns to the signaller as the receiver's assessed value of its attribute increases, or if, regardless of whether the Zahavian assumption holds, signallers with high values of the attribute benefit more from a given receiver assessment than signallers with low values (e.g. begging chicks that are hungrier benefit more from being fed). In stable systems of signalling among kin, it is also shown to be generally true that (i) levels of signalling and thus observed signal costs will decline as relatedness increases or as the receiver's reproductive penalty for erroneous assessment increases, and (ii) receivers will consistently, altruistically overestimate the true value of the signalled attribute.  
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  Notes Approved no  
  Call Number refbase @ user @ Serial 557  
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Author Tan, H.; Wilson, A.M. url  openurl
  Title Grip and limb force limits to turning performance in competition horses Type Journal Article
  Year 2011 Publication (down) Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal  
  Volume 278 Issue 1715 Pages 2105-2111  
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  Abstract Manoeuverability is a key requirement for successful terrestrial locomotion, especially on variable terrain, and is a deciding factor in predator–prey interaction. Compared with straight-line running, bend running requires additional leg force to generate centripetal acceleration. In humans, this results in a reduction in maximum speed during bend running and a published model assuming maximum limb force as a constraint accurately predicts how much a sprinter must slow down on a bend given his maximum straight-line speed. In contrast, greyhounds do not slow down or change stride parameters during bend running, which suggests that their limbs can apply the additional force for this manoeuvre. We collected horizontal speed and angular velocity of heading of horses while they turned in different scenarios during competitive polo and horse racing. The data were used to evaluate the limits of turning performance. During high-speed turns of large radius horizontal speed was lower on the bend, as would be predicted from a model assuming a limb force limit to running speed. During small radius turns the angular velocity of heading decreased with increasing speed in a manner consistent with the coefficient of friction of the hoof–surface interaction setting the limit to centripetal force to avoid slipping.  
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  Notes 10.1098/rspb.2010.2395 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5701  
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Author Scheffer, M.; van Nes, E.H. doi  openurl
  Title Self-organized similarity, the evolutionary emergence of groups of similar species Type Journal Article
  Year 2006 Publication (down) Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 103 Issue 16 Pages 6230-6235  
  Keywords Animals; *Competitive Behavior; *Ecosystem; *Evolution; *Models, Biological  
  Abstract Ecologists have long been puzzled by the fact that there are so many similar species in nature. Here we show that self-organized clusters of look-a-likes may emerge spontaneously from coevolution of competitors. The explanation is that there are two alternative ways to survive together: being sufficiently different or being sufficiently similar. Using a model based on classical competition theory, we demonstrate a tendency for evolutionary emergence of regularly spaced lumps of similar species along a niche axis. Indeed, such lumpy patterns are commonly observed in size distributions of organisms ranging from algae, zooplankton, and beetles to birds and mammals, and could not be well explained by earlier theory. Our results suggest that these patterns may represent self-constructed niches emerging from competitive interactions. A corollary of our findings is that, whereas in species-poor communities sympatric speciation and invasion of open niches is possible, species-saturated communities may be characterized by convergent evolution and invasion by look-a-likes.  
  Address Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 8080, 6700 DD, Wageningen, The Netherlands. marten.scheffer@wur.nl  
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  Series Volume Series Issue Edition  
  ISSN 0027-8424 ISBN Medium  
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  Notes PMID:16585519 Approved no  
  Call Number refbase @ user @ Serial 510  
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Author Dusek, J.A.; Eichenbaum, H. openurl 
  Title The hippocampus and memory for orderly stimulus relations Type Journal Article
  Year 1997 Publication (down) Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 94 Issue 13 Pages 7109-7114  
  Keywords Animals; Attention; Discrimination (Psychology)/physiology; Hippocampus/anatomy & histology/*physiology; Male; Memory/*physiology; Rats  
  Abstract Human declarative memory involves a systematic organization of information that supports generalizations and inferences from acquired knowledge. This kind of memory depends on the hippocampal region in humans, but the extent to which animals also have declarative memory, and whether inferential expression of memory depends on the hippocampus in animals, remains a major challenge in cognitive neuroscience. To examine these issues, we used a test of transitive inference pioneered by Piaget to assess capacities for systematic organization of knowledge and logical inference in children. In our adaptation of the test, rats were trained on a set of four overlapping odor discrimination problems that could be encoded either separately or as a single representation of orderly relations among the odor stimuli. Normal rats learned the problems and demonstrated the relational memory organization through appropriate transitive inferences about items not presented together during training. By contrast, after disconnection of the hippocampus from either its cortical or subcortical pathway, rats succeeded in acquiring the separate discrimination problems but did not demonstrate transitive inference, indicating that they had failed to develop or could not inferentially express the orderly organization of the stimulus elements. These findings strongly support the view that the hippocampus mediates a general declarative memory capacity in animals, as it does in humans.  
  Address Department of Psychology, Boston University, 64 Cummington Street, Boston, MA 02215, USA  
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  ISSN 0027-8424 ISBN Medium  
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  Notes PMID:9192700 Approved no  
  Call Number refbase @ user @ Serial 607  
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Author Jansen, T.; Forster, P.; Levine, M.A.; Oelke, H.; Hurles, M.; Renfrew, C.; Weber, J.; Olek, K. doi  openurl
  Title Mitochondrial DNA and the origins of the domestic horse Type Journal Article
  Year 2002 Publication (down) Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 99 Issue 16 Pages 10905-10910  
  Keywords Animals; Animals, Domestic/classification/*genetics; Base Sequence; DNA, Complementary; *DNA, Mitochondrial; *Evolution, Molecular; Horses/classification/*genetics; Molecular Sequence Data; Phylogeny  
  Abstract The place and date of the domestication of the horse has long been a matter for debate among archaeologists. To determine whether horses were domesticated from one or several ancestral horse populations, we sequenced the mitochondrial D-loop for 318 horses from 25 oriental and European breeds, including American mustangs. Adding these sequences to previously published data, the total comes to 652, the largest currently available database. From these sequences, a phylogenetic network was constructed that showed that most of the 93 different mitochondrial (mt)DNA types grouped into 17 distinct phylogenetic clusters. Several of the clusters correspond to breeds and/or geographic areas, notably cluster A2, which is specific to Przewalski's horses, cluster C1, which is distinctive for northern European ponies, and cluster D1, which is well represented in Iberian and northwest African breeds. A consideration of the horse mtDNA mutation rate together with the archaeological timeframe for domestication requires at least 77 successfully breeding mares recruited from the wild. The extensive genetic diversity of these 77 ancestral mares leads us to conclude that several distinct horse populations were involved in the domestication of the horse.  
  Address Biopsytec Analytik GmbH, Marie-Curie-Strasse 1, 53359 Rheinbach, Germany. jansen@biopsytec.com  
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  ISSN 0027-8424 ISBN Medium  
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  Notes PMID:12130666 Approved no  
  Call Number refbase @ user @ Serial 772  
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Author Cameron, E.Z.; Setsaas, T.H.; Linklater, W.L. url  doi
openurl 
  Title Social bonds between unrelated females increase reproductive success in feral horses Type Journal Article
  Year 2009 Publication (down) Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 106 Issue 33 Pages 13850-13853  
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  Abstract In many mammals, females form close social bonds with members of their group, usually between kin. Studies of social bonds and their fitness benefits have not been investigated outside primates, and are confounded by the relatedness between individuals in primate groups. Bonds may arise from kin selection and inclusive fitness rather than through direct benefits of association. However, female equids live in long-term social groups with unrelated members. We present 4 years of behavioral data, which demonstrate that social integration between unrelated females increases both foal birth rates and survival, independent of maternal habitat quality, social group type, dominance status, and age. Also, we show that such social integration reduces harassment by males. Consequently, social integration has strong direct fitness consequences between nonrelatives, suggesting that social bonds can evolve based on these direct benefits alone. Our results support recent studies highlighting the importance of direct benefits in maintaining cooperative behavior, while controlling for the confounding influence of kinship.  
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  Notes 10.1073/pnas.0900639106 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5152  
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Author Begall, S.; Cervený, J.; Neef, J.; Vojtech, O.; Burda, H. url  doi
openurl 
  Title Magnetic alignment in grazing and resting cattle and deer Type Journal Article
  Year 2008 Publication (down) Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 105 Issue 36 Pages 13451-13455  
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  Abstract We demonstrate by means of simple, noninvasive methods (analysis of satellite images, field observations, and measuring “deer beds” in snow) that domestic cattle (n = 8,510 in 308 pastures) across the globe, and grazing and resting red and roe deer (n = 2,974 at 241 localities), align their body axes in roughly a north–south direction. Direct observations of roe deer revealed that animals orient their heads northward when grazing or resting. Amazingly, this ubiquitous phenomenon does not seem to have been noticed by herdsmen, ranchers, or hunters. Because wind and light conditions could be excluded as a common denominator determining the body axis orientation, magnetic alignment is the most parsimonious explanation. To test the hypothesis that cattle orient their body axes along the field lines of the Earth's magnetic field, we analyzed the body orientation of cattle from localities with high magnetic declination. Here, magnetic north was a better predictor than geographic north. This study reveals the magnetic alignment in large mammals based on statistically sufficient sample sizes. Our findings open horizons for the study of magnetoreception in general and are of potential significance for applied ethology (husbandry, animal welfare). They challenge neuroscientists and biophysics to explain the proximate mechanisms.  
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  Notes 10.1073/pnas.0803650105 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5316  
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Author Young, H.P. url  openurl
  Title The dynamics of social innovation Type Journal Article
  Year 2011 Publication (down) Proceedings of the National Academy of Sciences Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.  
  Volume 108 Issue Supplement 4 Pages 21285-21291  
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  Notes 10.1073/pnas.1100973108 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5940  
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Author Harvey, P.H.; Clutton-Brock, T.H.; Mace, G.M. url  openurl
  Title Brain size and ecology in small mammals and primates Type Journal Article
  Year 1980 Publication (down) Proceedings of the National Academy of Sciences Abbreviated Journal PNAS  
  Volume 77 Issue 7 Pages 4387-4389  
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  Call Number Equine Behaviour @ team @ Serial 5456  
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