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Author Mori, A.; Iwamoto, T.; Bekele, A.
Title A case of infanticide in a recently found gelada population in Arsi, Ethiopia Type Journal Article
Year 1997 Publication Primates Abbreviated Journal Primates
Volume 38 Issue 1 Pages 79-88
Keywords heropithecus gelada – Infanticide – Male takeover – Leadership change
Abstract Abstract  There have been no reports of infanticide in wild gelada baboons and it has been argued that infanticide is not necessary in geladas, since the birth interval of female gelada can be shortened after takeover of a unit by a new leader male without infanticide. However, we observed an instance of infanticide in a newly-found wild gelada population in the Arsi Region of Ethiopia. After a leader male of the unit was severely wounded by a leopard attack, he was quite weakened. The second male of the unit, a young adult male, became the leader of the unit three weeks later, but the former leader continued to stay in the unit as a second male. After a week, two other adult males joined the unit which, therefore, came to include four adult males. The infanticide took place nine days later. The perpetrator was one of the immigrant males and he showed great interest in the mother of the unweaned victim infant. Although the perpetrator copulated with her after the infanticide, the usurper was found to own all three adult females after two weeks following the infanticide; i.e. the perpetrator could not own any female. The wounded former leader showed conspicuous protective behavior towards the victim's mother and the dead infant. One possible explanation for the occurrence of infanticide in this population of geladas is as follows. Gelada males in this area may be able to join units more easily to form multi-male units but then have shorter tenure in the units. Facing the unstable condition of units, they may sometimes engage in infanticide to increase their breeding opportunities, even before becoming a leader.
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Notes Approved no
Call Number (up) Serial 2061
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Author Di Bitetti, M.S.
Title Evidence for an important social role of allogrooming in a platyrrhine primate Type Journal Article
Year 1997 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 54 Issue 1 Pages 199-211
Keywords
Abstract Allogrooming behaviour was analysed in a wild group of tufted capuchin monkeys,Cebus apellain Iguazu National Park, Argentina. Evidence is provided that allogrooming in this platyrrhine species serves an important social function, as has been demonstrated for catarrhine primates. Using ad libitum sampling, 654 grooming sessions were recorded during 740 contact hours with one group. Seasonal variation was found in daily time allocation to allogrooming and the mean duration and reciprocity of sessions. Individual dominance rank was an important determinant of grooming relationships. The dominant male and female were the most actively involved in grooming. Among adults, dominant individuals were involved in more sessions than were subordinate individuals. The females maintained strong grooming relationships with each other and tended to reciprocate more within sessions than did males. Oestrous females engaged in more grooming bouts with adult males than did non-oestrous females. Females with newborn infants were attractive social partners for the remaining members of the group. A social function for allogrooming inCebusis indicated by the close relationship between allogrooming, the social system and coalition formation, and by the changes in quantity and direction of grooming in response to oestrous behaviour and to the birth of infants.
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Notes Approved no
Call Number (up) Serial 2079
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Author Joffe, T.H.; Dunbar, R.I.
Title Visual and socio-cognitive information processing in primate brain evolution Type Journal Article
Year 1997 Publication Proceedings. Biological Sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume 264 Issue 1386 Pages 1303-1307
Keywords Animals; Brain/anatomy & histology/*physiology; Cognition/physiology; *Evolution; Geniculate Bodies/anatomy & histology/physiology; Humans; Mental Processes/physiology; Neocortex/physiology; Primates/anatomy & histology/*physiology/*psychology; *Social Behavior; Visual Cortex/anatomy & histology/physiology
Abstract Social group size has been shown to correlate with neocortex size in primates. Here we use comparative analyses to show that social group size is independently correlated with the size of non-V1 neocortical areas, but not with other more proximate components of the visual system or with brain systems associated with emotional cueing (e.g. the amygdala). We argue that visual brain components serve as a social information 'input device' for socio-visual stimuli such as facial expressions, bodily gestures and visual status markers, while the non-visual neocortex serves as a 'processing device' whereby these social cues are encoded, interpreted and associated with stored information. However, the second appears to have greater overall importance because the size of the V1 visual area appears to reach an asymptotic size beyond which visual acuity and pattern recognition may not improve significantly. This is especially true of the great ape clade (including humans), that is known to use more sophisticated social cognitive strategies.
Address School of Life Sciences, University of Liverpool, UK
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Publisher Place of Publication Editor
Language English Summary Language Original Title
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ISSN 0962-8452 ISBN Medium
Area Expedition Conference
Notes PMID:9332015 Approved no
Call Number (up) Serial 2095
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Author Bateson, M.; Kacelnik, A.
Title Starlings' preferences for predictable and unpredictable delays to food Type Journal Article
Year 1997 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 53 Issue 6 Pages 1129-1142
Keywords
Abstract Risk-sensitive foraging theory is based on the premise that unpredictable runs of good or bad luck can cause a variable food source to differ in fitness value from a fixed food source yielding the same average rate of gain but no unpredictability. Thus, risk-sensitive predictions are dependent on the food intake from variable sources being not only variable but also unpredictable or `risky' in outcome. This study tested whether unpredictability is a component of the value that foraging starlings,Sturnus vulgarisattribute to food sources that are variable in the delay to obtain food. Two groups of birds chose between a fixed and a variable delay option; the variable option was unpredictable in the risky group and predictable in the risk-free group in the overall rate of intake it yielded. In both groups the fixed option was adjusted by titration to quantify the magnitude of preference for predictable and unpredictable variance. On negative energy budgets both groups were significantly risk-prone, with the risky group being significantly more risk-prone than the risk-free group. Switching the birds to positive budgets by doubling the size of each food reward had no significant effect on preference, and similar trends to those found with negative budgets were observed. These results are not readily explained by risk-sensitive foraging theory, but may be explained by the algorithm used by the birds to attribute value to average expected rewards.
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Notes Approved no
Call Number (up) Serial 2108
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Author Livoreil, B.; Giraldeau, L.
Title Patch departure decisions by spice finches foraging singly or in groups Type Journal Article
Year 1997 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 54 Issue 4 Pages 967-977
Keywords
Abstract The marginal value theorem predicts that when resources are clumped in space, a forager can maximize its rate of intake by deciding to leave a patch when its current feeding rate falls below the average for the habitat. A group version of the model predicts that when rate-maximizing group members share a patch, they should leave sooner, and each with less gain, than single animals exploiting the same patch. We tested these predictions in the laboratory by measuring patch departure decisions of spice finches, Lonchura punctulataexploiting food patches alone or in groups of three under two habitats that require different travel times. As predicted, group members left the patch sooner and with fewer seeds than single foragers. Unlike the model's assumptions, however, birds did not share the patch equally, and their exploitation curves could not be simply derived from those of single foragers. Grouping decreased the effect of travel time on patch exploitation. Moreover, within each group the bird expected to leave first delayed its departure although it collected fewer seeds than the others. This delayed departure could aim to maintain group membership. We noted an increased variability in seed number collected by group members compared with single foragers, which could be a cost of group foraging.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour
Address Department of Biology, Concordia University
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ISSN 0003-3472 ISBN Medium
Area Expedition Conference
Notes PMID:9344448 Approved no
Call Number (up) Serial 2138
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Author Hoff, M.P.; Powell, D.M.; Lukas, K.E.; Maple, T.L.
Title Individual and social behavior of lowland gorillas in outdoor exhibits compared with indoor holding areas Type Journal Article
Year 1997 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 54 Issue 4 Pages 359-370
Keywords Behavior; Agonistic behavior; Spatial distribution; Primates; Social behavior; Housing; Zoo animals; Gorilla
Abstract The behavior of nine lowland gorillas (Gorilla gorilla gorilla) living in three social groups at Zoo Atlanta was compared in an indoor holding area versus an outdoor exhibit. Focal animal data were collected for each animal during 15 min observation sessions, alternating between indoors and outdoors. A variety of solitary and social behaviors differed in the two conditions. All individual and social behaviors that showed a difference, except eating, occurred more indoors than outdoors. These included aggressive displays, reclining, self manipulation, and social examination of others. Additionally, the gorillas spent more time closer together in the indoor condition. A variety of other behaviors measured did not change between the two environments. There was a clear effect on behavior of the different housing conditions in which the gorillas were kept. It is suggested that the differences in aggressive behavior may be related to environmental complexity. It is further suggested that zoos should be aware that differences in behavior reported by caretaking staff, researchers and visitors may be a reflection of the differing environmental circumstances in which the animals are observed.
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Notes Approved no
Call Number (up) Serial 2143
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Author Khalil, A.M.; Kaseda, Y.
Title Behavioral patterns and proximate reason of young male separation in Misaki feral horses Type Journal Article
Year 1997 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 54 Issue 4 Pages 281-289
Keywords Misaki feral horse; Horse maternal-filial bond; Social behavior; Separation season; Separation reason
Abstract The present investigation was undertaken to study the proximate reasons why and the behavioral patterns of young male Misaki feral horses when they left their natal band or mothers. We observed a total of ten young males twice a month from January 1988 to December 1995. Almost all young males left their natal band or mothers at between 1 and 4 years of age. We found that, during the separation process, all the young males from first parity dams returned several times after the initial separation, indicating a strong attachment between primiparous mares and their male offspring. The other five separated only once without rejoining. Our observations showed five variable behavior patterns of young males at separation time, depending on the consort relation between their mothers and harem stallion and the reason for separation at that time. Eight young males separated in the non-breeding season at average 2.1 years and the other two separated in the breeding season at average 3 years and the average difference was not significant. These results revealed that 80% of the young males separated voluntarily when the natural resources become poor whereas 20% separated when their siblings were born.
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Notes Approved no
Call Number (up) Equine Behaviour @ team @ Serial 2209
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Author Castley, J.G.; Knight, M.H.
Title Population status of plains zebra, Equus burchelli, in South African National Parks. Type Journal Article
Year 1997 Publication Scientific Services, National Parks Board Abbreviated Journal
Volume Issue Pages
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Publisher Place of Publication Kimberley, South Africa. Editor
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Notes Approved no
Call Number (up) Equine Behaviour @ team @ Serial 2254
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Author Dellert, B.; Ganslosser, U.
Title Experimental alterations of food distribution in two species of captive equids (Equus burchelli and E. hemionus kulan) Type Journal Article
Year 1997 Publication Ethology Ecology & Evolution (EEE) Abbreviated Journal Ethol Ecol Evol
Volume 9 Issue 1 Pages 1-17
Keywords
Abstract n one group each of Plains zebra (six mares, one foal, one subadult) and Asiatic wild asses (seven mares, two foals) at Nuremberg Zoo, food distribution was experimentally changed from clumped (all food in one standard hay rack) to dispersed (one heap per animal). Both groups were characterized by different social structures, which basically remained during the experiment. Plains zebras had an individually structured system of social relationships in a dominance order, wild asses a more egalitarian system without clear-cut rank differences and low frequencies of agonistic interactions. Access to food accordingly was individually (but consistently) different for zebra mares, almost equal for wild ass mares. During the dispersed feeding situation frequencies of agonistic interactions in both species decreased (however non-significantly), individual distances increased but mares also frequently ''visited'' each others' heaps. Feeding time increased for all wild ass mares. Some individuals (in both groups) behaved ''against the trend'' in agonistic behaviour. The results are discussed with regard to food distribution for ungulates in general, and equid social systems.
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Notes Approved no
Call Number (up) Equine Behaviour @ team @ Serial 2292
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Author Monard, A.-M.; Duncan, P.; Fritz, H.; Feh, C.
Title Variations in the birth sex ratio and neonatal mortality in a natural herd of horses Type Journal Article
Year 1997 Publication Behavioral Ecology and Sociobiology Abbreviated Journal Behav. Ecol. Sociobiol.
Volume 41 Issue 4 Pages 243-249
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Abstract Variations in birth sex ratios and sex differences in juvenile mortality occur in a number of mammalian species, and in many cases have been linked to resource availability. Most of these biases in offspring sex ratios concern polygynous species with pronounced sexual dimorphism, and where females only are philopatric. Data on species with unusual life-history strategies, such as slight sexual dimorphism or dispersal by both sexes, are of particular interest. In this study of a natural herd of horses (Equus caballus) which experienced an eruptive cycle, and therefore a period of nutritional stress, male offspring had higher neonatal mortality rates in nutritionally poor years than in good ones, whereas “year quality” had no effect on the mortality of female offspring; year quality could therefore be used by mares as predictor of sex-specific offspring survival. We show that the environmental conditions that predicted lower survival of males were negatively related to their production: the birth sex ratio the following year was female-biased; and mares were less likely to produce a son when they had produced a son the preceding year. There was no significant effect of mother's parity, age or rank, or the timing of conception or birth on offspring sex ratios. The mechanism leading to biases in the birth sex ratio could have been the loss of male embryos by mares that did not foal. As there was no evidence for selective abortion of male foetuses in females that did foal the next year, it is not necessary to invoke maternal adjustment, though this remains a possibility. Finally, there was a suggestion that male offspring were more costly to raise than females, since mothers that reared a son in poor years tended to experience an increase in the interbirth interval between their two subsequent offspring.
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Notes Approved no
Call Number (up) Equine Behaviour @ team @ Serial 2388
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