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Author Noë, R.; van Schaik, C.P.; van Hooff, J.A.R.A.M. url  doi
openurl 
  Title The Market Effect: an Explanation for Pay-off Asymmetries among Collaborating Animals Type Journal Article
  Year 1991 Publication Ethology Abbreviated Journal Ethology  
  Volume 87 Issue 1-2 Pages 97-118  
  Keywords  
  Abstract Abstract * 1Animals can derive leverage over others from (a) resource holding power, based for instance on fighting ability or dominance, and (b) the possession of commodities, such as special skills and resources that cannot be taken away by force. * 2We contend that power based on the possession of commodities strongly depends on the level of supply and demand for that commodity, a phenomenon we call the ‘market effect’. * 3Several theoretical and empirical examples are given of social systems in which animals belong to two distinct classes that offer two different kinds of commodities. * 4The relative frequency of occurrence of the two classes is shown to determine the relative power of their members. * 5We consider the theoretical properties of bargaining processes by which relative power is converted into corresponding pay-off distributions. * 6We propose coalition games, a class of games with more than two players and in which bargaining is possible, as suitable paradigms for collaboration among members of social units.  
  Address  
  Corporate Author Thesis  
  Publisher Blackwell Publishing Ltd Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1439-0310 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5413  
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Author Potts, W.K.; Manning, C.J.; Wakeland, E.K. url  doi
openurl 
  Title Mating patterns in seminatural populations of mice influenced by MHC genotype Type Journal Article
  Year 1991 Publication Nature Abbreviated Journal Nature  
  Volume 352 Issue 6336 Pages 619-621  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes 10.1038/352619a0 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5424  
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Author Judge, P.J. url  doi
openurl 
  Title Dyadic and triadic reconciliation in pigtail macaques (Macaca nemestrina) Type Journal Article
  Year 1991 Publication Am. J. Primatol. Abbreviated Journal  
  Volume 23 Issue Pages 225-237  
  Keywords reconciliation • kinship • affiliation • aggression  
  Abstract The tendency in primates for former antagonists to approach and affiliate following aggression has been termed reconciliation because the response is thought to resolve social conflicts produced by aggression. In primate societies, however, an aggressive interaction between two individuals often spreads to include other group members, especially the kin of the combatants. If post conflict affiliation resolves aggressive conflicts in a group, then affiliative increases might occur between combatants and the kin of their opponents following aggression as well as between former opponents. This hypothesis was tested in a captive group of 39 pigtail macaques (Macaca nemestrina) by comparing affiliative response frequencies of combatants during the 5 minute period following aggression to affiliative response frequencies during 5 minute baseline periods not preceded by aggressive activity. Following aggression, affiliation rates increased between combatants and their opponents, aggressors and the kin of their opponents, and aggressors and their own kin. Additional analyses showed that aggression among kin was reconciled more often than aggression among nonkin. Recipients of aggression reconciled with their attackers more often than aggressors reconciled with their victims. Animals with similar dominance ranks reconciled proportionately more often than those with large rank disparities and aggressive infractions of a calculated dominance hierarchy were reconciled more often than attacks consistent with the hierarchy. Results suggest that both dyadic and triadic reconciliations occur in M. nemestrina and that compared to other primate species M. nemestrina exhibit a moderate-to-high conciliatory tendency.  
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  Area Expedition Conference  
  Notes 10.1002/ajp.1350230403 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4869  
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Author Garott, R.A. doi  openurl
  Title Sex Ratios and Differential Survival of Feral Hors Type Journal Article
  Year 1991 Publication Journal of Animal Ecology Abbreviated Journal J Anim Ecol  
  Volume 60 Issue 3 Pages 929-936  
  Keywords  
  Abstract (1) Sex and age data were collected on 60 111 feral horses (Equus caballus L.) removed from eighty-nine areas in Nevada, Wyoming, and Oregon between 1976 and 1987. (2) Sex ratios of young seldom differed from parity; however, sex ratios of adults were commonly skewed toward females. No evidence of differential capture probability between adult males and females could be detected; therefore, skewed adult sex ratios were attributed to differential survival. (3) Age-specific trends in sex ratios indicated that the proportion of males steadily decreased from near parity in foals, to lows of 0.61-0.77 in the 4-5-year age-classes. The trend then reversed with males becoming predominant (1.08-1.36) in the > 10 years age-class. (4) Population simulations suggest that survival diffentials of 0.05-0.07, favouring females to 4 years of age, and 0.02-0.04 favouring males in older age-classes were required to mimic observed age-specific sex ratio changes. To obtain the high proportion of males in the > 10-years age-class, onset of senescence also had to be earlier for females. (5) Causes for differential survival in the immature age-classes are uncertain, but may relate to behavioural or metabolic differences between the sexes. Differential survival between adult males and females is attributed to differences in the energetic costs of reproduction and disparity in their reproductive life spans.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 2294  
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Author Dougherty, D.M.; Lewis, P. doi  openurl
  Title Stimulus generalization, discrimination learning, and peak shift in horses Type Journal Article
  Year 1991 Publication Journal of the experimental analysis of behavior Abbreviated Journal J Exp Anal Behav  
  Volume 56 Issue 1 Pages 97-104  
  Keywords Animals; *Appetitive Behavior; Attention; *Conditioning, Operant; *Discrimination Learning; Female; *Generalization, Stimulus; Horses/*psychology; Male; *Pattern Recognition, Visual; Size Perception  
  Abstract Using horses, we investigated three aspects of the stimulus control of lever-pressing behavior: stimulus generalization, discrimination learning, and peak shift. Nine solid black circles, ranging in size from 0.5 in. to 4.5 in. (1.3 cm to 11.4 cm) served as stimuli. Each horse was shaped, using successive approximations, to press a rat lever with its lip in the presence of a positive stimulus, the 2.5-in. (6.4-cm) circle. Shaping proceeded quickly and was comparable to that of other laboratory organisms. After responding was maintained on a variable-interval 30-s schedule, stimulus generalization gradients were collected from 2 horses prior to discrimination training. During discrimination training, grain followed lever presses in the presence of a positive stimulus (a 2.5-in circle) and never followed lever presses in the presence of a negative stimulus (a 1.5-in. [3.8-cm] circle). Three horses met a criterion of zero responses to the negative stimulus in fewer than 15 sessions. Horses given stimulus generalization testing prior to discrimination training produced symmetrical gradients; horses given discrimination training prior to generalization testing produced asymmetrical gradients. The peak of these gradients shifted away from the negative stimulus. These results are consistent with discrimination, stimulus generalization, and peak-shift phenomena observed in other organisms.  
  Address Department of Psychology, Ohio University, Athens 45701  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-5002 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:1940765 Approved no  
  Call Number Serial 1764  
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Author Ben-Shahar, R doi  openurl
  Title Selectivity in large generalist herbivores: feeding patterns of African ungulates in a semi-arid habitat Type Journal Article
  Year 1991 Publication African Journal of Ecology Abbreviated Journal Afr. J. Ecol.  
  Volume 29 Issue 4 Pages 302-315  
  Keywords diet; forage production; grazing; wildebeest; zebra  
  Abstract Feeding habits of free-ranging wildebeest and zebra were monitored in a semi-arid nature reserve, bordering the southwestern part of Kruger National Park, South Africa. The purpose of study was to distinguish and define the feeding niches of two roughage grazers that occur in similar habitat types. The monthly compositions of diets were evaluated by direct observations of feeding bouts over a period of two years when rainfall patterns were average and animal populations were stable. Other analyses evaluated the standing biomass of grass species in the reserve during the wet summer and dry winter seasons.

A considerable overlap of grass species composition was found in the diets of wildebeest and zebra. Ordination of bi-monthly records of the diet composition showed greater variations in scores of grasses in zebra diet in comparison to wildebeest. Seasonal patterns were more apparent in the wildebeest diet. Preference ranking of grass species indicated that zebra diet remained constant in winter and summer. Wildebeest diet however, alternated with seasons, showing high preferences during the winter months for grass species which were rejected during summer.

The combined assessment of results from three separate statistical methods analysing temporal patterns and preferences in diet composition revealed contradictory trends. The solution, however, relied on the initial assumptions posed. Hence, wildebeest and zebra are essentially generalist feeders which show a limited amount of preference in their choice of diet.
 
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 2226  
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Author Marean, C.W.; Gifford-Gonzalez, D. doi  openurl
  Title Late Quaternary extinct ungulates of East Africa and palaeoenvironmental implications Type Journal Article
  Year 1991 Publication Nature Abbreviated Journal Nature  
  Volume 350 Issue 6317 Pages 418-420  
  Keywords  
  Abstract UNGULATE communities of two East African savannas, the Serengeti and Athi-Kapiti Plains, are dominated by wildebeest (Connochaetes taurinus) supplemented by zebra (Equus burchelli), topi (Damaliscus lunatus), hartebeest (Alcelaphus buselaphus), buffalo (Syncerus caffer) eland (Taurotragus oryx) and gazelles (Gazella grand and G. thomsoni)1-3. Before this research, little was known of East African large mammal communities in the Late Pleistocene and early to middle Holocene. We document an extinct impala-sized alcelaphine antelope that is numerically dominant in Late Pleistocene archaeofaunal assemblages from the Athi-Kapiti Plains. The extinct giant buffalo Pelorovis antiquus is present, and a number of arid-adapted regionally extinct species are common. The small alcelaphine is rare in northern Tanzania, but regionally extinct arid-adapted species are present in Late Pleistocene deposits. These data indicate that as recently as 12,000 years ago, the large mammal community structure of East African savannas was very different and dry grasslands and arid-adapted ungulates expanded at least as far south as northern Tanzania during the Last Glacial Maximum.  
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  Area Expedition Conference  
  Notes 10.1038/350418a0 Approved no  
  Call Number Equine Behaviour @ team @ Serial 2345  
Permanent link to this record
 

 
Author Pepperberg, I.M.; Brezinsky, M.V. doi  openurl
  Title Acquisition of a relative class concept by an African gray parrot (Psittacus erithacus): discriminations based on relative size Type Journal Article
  Year 1991 Publication Journal of Comparative Psychology Abbreviated Journal J Comp Psychol  
  Volume 105 Issue 3 Pages 286-294  
  Keywords Animals; Aptitude; *Concept Formation; *Discrimination Learning; Form Perception; Male; Mental Recall; *Parrots; *Size Perception; Vocalization, Animal  
  Abstract We report that an African gray parrot (Psittacus erithacus), Alex, responds to stimuli on a relative basis. Previous laboratory studies with artificial stimuli (such as pure tones) suggest that birds make relational responses as a secondary strategy, only after they have acquired information about the absolute values of the stimuli. Alex, however, after learning to respond to a small set of exemplars on the basis of relative size, transferred this behavior to novel situations that did not provide specific information about the absolute values of the stimuli. He responded to vocal questions about which was the larger or smaller exemplar by vocally labeling its color or material, and he responded “none” if the exemplars did not differ in size. His overall accuracy was 78.7%.  
  Address Northwestern University  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. : 1983 Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0735-7036 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:1935007 Approved yes  
  Call Number Equine Behaviour @ team @ Serial 3610  
Permanent link to this record
 

 
Author Penzhorn,B.L.; Novellie, P.A. doi  openurl
  Title Some behavioural traits of Cape mountain zebras and their implications for the management of asmall conservation area Type Journal Article
  Year 1991 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.  
  Volume 29 Issue 1-4 Pages 293-299  
  Keywords  
  Abstract The social organisation of mountain zebras (Equus zebra zebra) consists of breeding herds (1 male, 2.4 females (range 1–5) and their offspring) which remain stable over many years, and bachelor groups. Foals leave their maternal herds of their own accord. In a free-ranging population the behaviour of the foals in leaving the herd is probably an adequate mechanism to prevent inbreeding, but inbreeding may occur in confined populations. Individual recognition by means of stripe pattern allows a check to be kept.

Seasonal movement of mountain zebras is associated with a relative change in diet quality (as indicated by crude protein contents of preferred food plants and of faeces) between summer and winter habitats. Any conservation area should be large and varied enough to include both summer and winter habitats. Mountain zebras favour taller grass than most antelope species, harvesting their food at 50–150 mm from the ground. The existence of large populations of antelope could, therefore, be detrimental to zebras.
 
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  Notes from Professor Hans Klingels Equine Reference List Approved no  
  Call Number Serial 1465  
Permanent link to this record
 

 
Author Penzhorn, B.L.; Novellie, P.A. doi  openurl
  Title Some behavioural traits of Cape mountain zebras (Equus zebra zebra) and their implications for the management of a small conservation area Type Journal Article
  Year 1991 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.  
  Volume 29 Issue 1-4 Pages 293-299  
  Keywords  
  Abstract The social organisation of mountain zebras (Equus zebra zebra) consists of breeding herds (1 male, 2.4 females (range 1-5) and their offspring) which remain stable over many years, and bachelor groups. Foals leave their maternal herds of their own accord. In a free-ranging population the behaviour of the foals in leaving the herd is probably an adequate mechanism to prevent inbreeding, but inbreeding may occur in confined populations. Individual recognition by means of stripe pattern allows a check to be kept. Seasonal movement of mountain zebras is associated with a relative change in diet quality (as indicated by crude protein contents of preferred food plants and of faeces) between summer and winter habitats. Any conservation area should be large and varied enough to include both summer and winter habitats. Mountain zebras favour taller grass than most antelope species, harvesting their food at 50-150 mm from the ground. The existence of large populations of antelope could, therefore, be detrimental to zebras.  
  Address  
  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0168-1591 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5074  
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