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Author (down) Cameron, E.Z.
Title Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism Type Journal Article
Year 2004 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume 271 Issue 1549 Pages 1723-1728
Keywords Age Factors; Animals; Body Constitution; *Evolution; Female; Glucose/metabolism/physiology; Litter Size; Male; Mammals/*physiology; *Models, Biological; Reproduction/physiology; Seasons; Sex Factors; *Sex Ratio; Time Factors
Abstract Evolutionary theory predicts that mothers of different condition should adjust the birth sex ratio of their offspring in relation to future reproductive benefits. Published studies addressing variation in mammalian sex ratios have produced surprisingly contradictory results. Explaining the source of such variation has been a challenge for sex-ratio theory, not least because no mechanism for sex-ratio adjustment is known. I conducted a meta-analysis of previous mammalian sex-ratio studies to determine if there are any overall patterns in sex-ratio variation. The contradictory nature of previous results was confirmed. However, studies that investigated indices of condition around conception show almost unanimous support for the prediction that mothers in good condition bias their litters towards sons. Recent research on the role of glucose in reproductive functioning have shown that excess glucose favours the development of male blastocysts, providing a potential mechanism for sex-ratio variation in relation to maternal condition around conception. Furthermore, many of the conflicting results from studies on sex-ratio adjustment would be explained if glucose levels in utero during early cell division contributed to the determination of offspring sex ratios.
Address Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa. ezcameron@zoology.up.ac.za
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0962-8452 ISBN Medium
Area Expedition Conference
Notes PMID:15306293 Approved no
Call Number refbase @ user @ Serial 413
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Author (down) Call J
Title Inferences about the location of food in the great apes (Pan paniscus, Pan troglodytes, Gorilla gorilla, and Pongo pygmaeus) Type Journal Article
Year 2004 Publication Journal of Comparative Psychology Abbreviated Journal J. Comp. Psychol.
Volume 118 Issue 2 Pages 232
Keywords
Abstract Bonobos (Pan paniscus; n = 4), chimpanzees (Pan troglodytes; n = 12), gorillas (Gorilla gorilla; n = 8), and orangutans (Pongo pygmaeus; n = 6) were presented with 2 cups (1 baited) and given visual or auditory information about their contents. Visual information consisted of letting subjects look inside the cups. Auditory information consisted of shaking the cup so that the baited cup produced a rattling sound. Subjects correctly selected the baited cup both when they saw or heard the food. Nine individuals were above chance in both visual and auditory conditions. More important, subjects as a group selected the baited cup when only the empty cup was either shown or shaken, which means that subjects chose correctly without having seen or heard the food (i.e., inference by exclusion). Control tests showed that subjects were not more attracted to noisy cups, avoided shaken noiseless cups, or learned to use auditory information as a cue during the study. It is concluded that subjects understood that the food caused the noise, not simply that the noise was associated with the food. (PsycINFO Database Record (c) 2010 APA, all rights reserved)
Address food location; inference ; apes;auditory information;visual information
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Notes Approved yes
Call Number Equine Behaviour @ team @ Serial 3057
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Author (down) Caldwell, C.A.; Whiten, A.
Title Testing for social learning and imitation in common marmosets, Callithrix jacchus, using an artificial fruit Type Journal Article
Year 2004 Publication Animal cognition Abbreviated Journal Anim. Cogn.
Volume 7 Issue 2 Pages 77-85
Keywords Animals; *Association Learning; Callithrix/*psychology; Discrimination Learning; *Feeding Behavior; Female; Food Preferences; Fruit; *Imitative Behavior; Male; *Social Behavior; Social Environment
Abstract We tested for social learning and imitation in common marmosets using an artificial foraging task and trained conspecific demonstrators. We trained a demonstrator marmoset to open an artificial fruit, providing a full demonstration of the task to be learned. Another marmoset provided a partial demonstration, controlling for stimulus enhancement effects, by eating food from the outside of the apparatus. We thus compared three observer groups, each consisting of four animals: those that received the full demonstration, those that received the partial demonstration, and a control group that saw no demonstration prior to testing. Although none of the observer marmosets succeeded in opening the artificial fruit during the test periods, there were clear effects of demonstration type. Those that saw the full demonstration manipulated the apparatus more overall, whereas those from the control group manipulated it the least of the three groups. Those from the full-demonstration group also contacted the particular parts of the artificial fruit that they had seen touched (localised stimulus enhancement) to a greater extent than the other two groups. There was also an interaction between the number of hand and mouth touches made to the artificial fruit for the full- and partial-demonstration groups. Whether or not these data represent evidence for imitation is discussed. We also propose that the clear differences between the groups suggest that social learning mechanisms provide real benefits to these animals in terms of developing novel food-processing skills analogous to the one presented here.
Address Centre for Social Learning and Cognitive Evolution and Scottish Primate Research Group, University of St Andrews, KY16 9JU, St Andrews, Fife, Scotland. C.A.Caldwell@exeter.ac.uk
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Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1435-9448 ISBN Medium
Area Expedition Conference
Notes PMID:15069606 Approved no
Call Number refbase @ user @ Serial 735
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Author (down) Bugnyar, T.; Stöwe, M.; Heinrich, B.
Title Ravens, Corvus corax, follow gaze direction of humans around obstacles Type Journal Article
Year 2004 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. Roy. Soc. Lond. B Biol. Sci.
Volume 271 Issue 1546 Pages 1331-1336
Keywords
Abstract The ability to follow gaze (i.e. head and eye direction) has recently been shown for social mammals, particularly primates. In most studies, individuals could use gaze direction as a behavioural cue without understanding that the view of others may be different from their own. Here, we show that hand–raised ravens not only visually co–orient with the look–ups of a human experimenter but also reposition themselves to follow the experimenter's gaze around a visual barrier. Birds were capable of visual co–orientation already as fledglings but consistently tracked gaze direction behind obstacles not before six months of age. These results raise the possibility that sub–adult and adult ravens can project a line of sight for the other person into the distance. To what extent ravens may attribute mental significance to the visual behaviour of others is discussed.
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Notes 10.1098/rspb.2004.2738 Approved no
Call Number Equine Behaviour @ team @ Serial 5009
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Author (down) Bugnyar, T.; Kotrschal, K.
Title Leading a conspecific away from food in ravens ( Corvus corax)? Type Journal Article
Year 2004 Publication Animal Cognition Abbreviated Journal Anim. Cogn.
Volume 7 Issue 2 Pages 69-76
Keywords Misleading – Deception – Raven – Social foraging
Abstract Active misleading of conspecifics has been described as a social strategy mainly for primates. Here we report a raven leading a competitor away from food in a social foraging task. Four individuals had to search and compete for hidden food at color-marked clusters of artificial food caches. At the beginning of the experiment, a subordinate male found and exploited the majority of the food. As a result, the dominant male displaced him from the already opened boxes. The subordinate male then developed a pattern, when the loss of reward to the dominant got high, of moving to unrewarded clusters and opening boxes there. This diversion often led the dominant to approach those unrewarded clusters and the subordinate then had a head start for exploiting the rewarded boxes. Subsequently, however, the dominant male learned not to follow the subordinate to unrewarded clusters and eventually started searching for the reward himself. These interactions between the two males illustrate the ravens' potential for deceptively manipulating conspecifics. We discuss under which circumstances ravens might use this capacity.
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Notes Approved no
Call Number Serial 2080
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Author (down) Bräuer, J.; Call, J.; Tomasello, M.
Title Visual perspective taking in dogs (Canis familiaris) in the presence of barriers Type Journal Article
Year 2004 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 88 Issue 3-4 Pages 299-317
Keywords Dogs; Visual perspective taking; Metacognition
Abstract Previous studies have shown that dogs have developed a special sensitivity to the communicative signals and attentional states of humans. The aim of the current study was to further investigate what dogs know about the visual perception of humans and themselves. In the first two experiments we investigated whether dogs were sensitive to the properties of barriers as blocking the visual access of humans. We presented dogs with a situation in which a human forbade them to take a piece of food, but the type and orientation of the barrier allowed the dog to take the food undetected in some conditions. Dogs differentiated between effective and ineffective barriers, based on their orientation or the particular features of the barriers such as size or the presence of window. In the third study we investigated whether dogs know about what they themselves have seen. We presented subjects with two boxes and placed food in one of them. In the Seen condition the location of the food was shown to the dogs while in the Unseen condition dogs were prevented from seeing the destination of the food. Before selecting one of the boxes by pressing a lever, dogs had the opportunity to seek extra information regarding the contents of the boxes, which would be particularly useful in the condition in which they had not seen where the food was hidden. Dogs rarely used the opportunity to seek information about the contents of the box before making their choice in any condition. Therefore, we found no evidence suggesting that dogs have access to what they themselves have seen, which contrasts with the positive evidence about visual perspective taking in others from the first two experiments and previous studies.
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Series Volume Series Issue Edition
ISSN 0168-1591 ISBN Medium
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Notes Approved no
Call Number Equine Behaviour @ team @ Serial 4986
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Author (down) Broucek, J., Uhrincat, M., KiÅ¡ac, P., Hanus, A..
Title Hair Whorl Position as a Predictor of Learning Ability and Locomotor Behavior in Cattle? Type Journal Article
Year 2004 Publication ACTA VETERINARIA BRUNENSIS Abbreviated Journal ACTA VET. BRNO
Volume 73 Issue 4 Pages 455-459
Keywords Cattle, hair whorl, reversal learning, open-field
Abstract The aim of our work was to investigate the hypothesis that the speed of solving the maze tests and

locomotor behavior of heifers in open-field tests are affected by the height location of facial whorl.

Fifty-eight Holstein heifers were used. Maze learning was observed at the age of 15 weeks, and an

open-field test was applied at two ages, 16 weeks and 18 months. Whorl placement was recorded by

one person as each heifer entered the scale. The hair whorl position was determined on the basis of

two patterns: A) hair whorl high, middle and low and B) hair whorl high and low. Heifers with a

high hair whorl were the fastest (77.8 ± 84.3 s) and heifers with a middle hair whorl the slowest (87.3

± 100.3 s) in the A pattern during the maze tests. In the B whorl pattern, heifers with a high hair whorl

ran across the maze in 84.5 ± 95.2 s and heifers with a low hair whorl in 84.1 ± 97.9 s. The number

of crossed squares in a 5-minute open-field test in the A pattern was the non-significantly highest in

heifers with a high hair whorl (43.4) at the age of 16 weeks. In the B whorl pattern, heifers with a

high hair whorl were also more mobile, but neither differences in individual minutes nor in the whole

5 minutes were significant. Heifers with a high hair whorl displayed the strongest locomotory

behavior (37.6 squares) and heifers with a low hair whorl (30.8) were the slowest in the A pattern at

the age of 18 months. The differences were not significant. In the B whorl pattern, heifers with a

high hair whorl crossed more squares, but the difference was not significant in comparison with

heifers with a low hair whorl. We found that the time of traversing the maze and the locomotor

activity in open-field test may not be influenced in the dairy cattle by the height facial whorl position
Address
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Notes Approved no
Call Number Equine Behaviour @ team @ Serial 4321
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Author (down) Brosnan, S.F.; de Waal, F.B.M.
Title A concept of value during experimental exchange in brown capuchin monkeys, Cebus apella Type Journal Article
Year 2004 Publication Folia primatologica; international journal of primatology Abbreviated Journal Folia Primatol (Basel)
Volume 75 Issue 5 Pages 317-330
Keywords Animals; Cebus/*psychology; *Choice Behavior; Female; Food Preferences; *Learning; Male; Sex Factors; Statistics, Nonparametric; *Token Economy; Video Recording
Abstract We evaluated the response of brown capuchin monkeys to two differentially valued tokens in an experimental exchange situation akin to a simple barter. Monkeys were given a series of three tests to evaluate their ability to associate tokens with food, then their responses were examined in a barter situation in which tokens were either limited or unlimited. Capuchins did not perform barter in the typical sense, returning the tokens which were associated with the reward. However, females, but not males, showed a different response, preferring the higher-value token. This may indicate that they learned to prefer one token over the other rather than to associate the tokens with their specific rewards. This sex difference parallels previous findings of greater reciprocity in female brown capuchins than in males.
Address Living Links Center, Emory University, Yerkes National Primate Research Center, 954 N. Gatewood Drive, Atlanta, GA 30329, USA. sbrosna@emory.edu
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0015-5713 ISBN Medium
Area Expedition Conference
Notes PMID:15486443 Approved no
Call Number refbase @ user @ Serial 170
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Author (down) Brosnan, S.F.; de Waal, F.B.M.
Title Socially learned preferences for differentially rewarded tokens in the brown capuchin monkey (Cebus apella) Type Journal Article
Year 2004 Publication Journal of comparative psychology (Washington, D.C. : 1983) Abbreviated Journal J Comp Psychol
Volume 118 Issue 2 Pages 133-139
Keywords Animals; Behavior, Animal; Cebus; *Choice Behavior; Female; *Learning; Male; *Reward; *Social Behavior
Abstract Social learning is assumed to underlie traditions, yet evidence indicating social learning in capuchin monkeys (Cebus apella), which exhibit traditions, is sparse. The authors tested capuchins for their ability to learn the value of novel tokens using a previously familiar token-exchange economy. Capuchins change their preferences in favor of a token worth a high-value food reward after watching a conspecific model exchange 2 differentially rewarded tokens, yet they fail to develop a similar preference after watching tokens paired with foods in the absence of a conspecific model. They also fail to learn that the value of familiar tokens has changed. Information about token value is available in all situations, but capuchins seem to pay more attention in a social situation involving novel tokens.
Address Living Links Center, Yerkes National Primate Research Center, and Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA 30329, USA. sbrosna@emory.edu
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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:15250800 Approved no
Call Number refbase @ user @ Serial 173
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Author (down) Brennan, P.A.
Title The nose knows who's who: chemosensory individuality and mate recognition in mice Type Journal Article
Year 2004 Publication Hormones and Behavior Abbreviated Journal Horm Behav
Volume 46 Issue 3 Pages 231-240
Keywords Animals; Chemoreceptors/physiology; Discrimination Learning/*physiology; Embryo Implantation/physiology; Female; Individuality; Major Histocompatibility Complex/physiology; Male; Mice; Neurons, Afferent/physiology; Nose/cytology/physiology; Perception/physiology; Pregnancy; Pregnancy Maintenance/physiology; Pregnancy, Animal/*physiology; Receptors, Odorant/*physiology; Recognition (Psychology)/*physiology; Sexual Behavior, Animal/*physiology; Smell/*physiology; Urine/physiology; Vomeronasal Organ/cytology/physiology
Abstract Individual recognition is an important component of behaviors, such as mate choice and maternal bonding that are vital for reproductive success. This article highlights recent developments in our understanding of the chemosensory cues and the neural pathways involved in individuality discrimination in rodents. There appear to be several types of chemosensory signal of individuality that are influenced by the highly polymorphic families of major histocompatibility complex (MHC) proteins or major urinary proteins (MUPs). Both have the capability of binding small molecules and may influence the individual profile of these chemosignals in biological fluids such as urine, skin secretions, or saliva. Moreover, these proteins, or peptides associated with them, can be taken up into the vomeronasal organ (VNO) where they can potentially interact directly with the vomeronasal receptors. This is particularly interesting given the expression of major histocompatibility complex Ib proteins by the V2R class of vomeronasal receptor and the highly selective responses of accessory olfactory bulb (AOB) mitral cells to strain identity. These findings are consistent with the role of the vomeronasal system in mediating individual discrimination that allows mate recognition in the context of the pregnancy block effect. This is hypothesized to involve a selective increase in the inhibitory control of mitral cells in the accessory olfactory bulb at the first level of processing of the vomeronasal stimulus.
Address Sub-Department of Animal Behaviour, University of Cambridge, Madingley, Cambridge CB3 8AA, UK. pab23@cus.cam.ac.uk
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0018-506X ISBN Medium
Area Expedition Conference
Notes PMID:15325224 Approved no
Call Number Equine Behaviour @ team @ Serial 4191
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