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Bugnyar, T., & Kotrschal, K. (2002). Observational learning and the raiding of food caches in ravens, Corvus corax: is it `tactical' deception? Anim. Behav., 64(2), 185–195.
Abstract: Group-foraging ravens scatter-hoard when they are competing for food and, to some extent, also raid the caches made by others. We investigated the effects of observational spatial memory on individual caching and raiding tactics. With captive ravens, we found visual observation was essential for locating and raiding the caches of conspecifics. Both captive and free-ranging ravens, food cachers as well as potential cache raiders, responded to each other's presence. Cachers withdrew from conspecifics and most often placed their caches behind structures, obstructing the view of potential observers. Raiders watched inconspicuously and kept at a distance to cachers close to their cache sites. In response to the presence of potential raiders or because of their initial movements towards caches, the cachers frequently interrupted caching, changed cache sites, or recovered their food items. These results suggest that ravens, regardless of whether they act as cachers or raiders, are capable of withholding information about their intentions and, hence, manipulate the other bird's attention either to prevent or to achieve social-learning opportunities. Such interactions may qualify as `tactical' deception and may have created a considerable pressure selecting for social cognition in ravens. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.
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Appleby, M. (2002). Consciousness, Cognition and Animal Welfare: J.K. Kirkwood, R.C. Hubrecht, S. Wickens, H. O'Leary, S. Oakley (Eds.), Universities Federation for Animal Welfare, 2001, 251 pp., Paperback, Supplement to Volume 10 of Animal Welfare, [pound sign]15/US$ 30, ISSN 0962-7286. Appl. Anim. Behav. Sci., 77(3), 239–241.
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Ligout, S., Porter, R. H., & Bon, R. (2002). Social discrimination in lambs: persistence and scope. Appl. Anim. Behav. Sci., 76(3), 239–248.
Abstract: Social recognition among familiar unrelated lambs was assessed in a series of tests. Lambs and their mothers were housed together in small groups for 1 week (Original groups; O) then reorganized into new groupings (Recent-groups; R) for the remainder of the experiment. During test series 1, lambs that were paired with a familiar O-group partner, from which they had been separated for 5 days, emitted fewer distress bleats than did those tested with an unfamiliar partner. This same effect was not evident when the test was repeated several hours later, indicating that the animals had become habituated to the testing procedures. Two days later, when given the choice between an O- versus a R-partner (test series 2), lambs did not display a preference for either of the stimulus lambs. However, in an additional two-choice test (test series 3) the subject lambs responded discriminatively to a recent familiar partner that was simultaneously present with an unfamiliar lamb. Overall, the results suggest that lambs are capable of developing discriminative relationships with age-mates from different sub-groups, and that such social discrimination persists over a separation period lasting at least several days. It is not clear whether lambs recognize several individual conspecifics per se or discriminate between members of higher order social categories (e.g. familiar versus unfamiliar individuals). Proximal and distal social discrimination may be mediated by different combinations of sensory modalities.
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Bracke, M. B. M., Spruijt, B. M., Metz, J. H. M., & Schouten, W. G. P. (2002). Decision support system for overall welfare assessment in pregnant sows A: Model structure and weighting procedure. J. Anim Sci., 80(7), 1819–1834.
Abstract: The problem of how to objectively assess the overall welfare status of animals under farming conditions has contributed to an ongoing debate that has hampered actual decision making on animal welfare. For this reason we constructed a model based on the assumed hierarchical organization of the animals' needs for overall welfare assessment in the case of pregnant sows. This model is implemented in a computer-based decision support system that takes a description of a housing and management system as input and produces a welfare score as output. A formalized procedure was used to construct the model for welfare assessment in pregnant sows on the basis of available scientific knowledge. This SOWEL (from SOw WELfare) model contains 37 attributes that describe the welfare-relevant properties of housing and management systems. In the decision support system these attributes are linked to scientific statements and a list of needs to provide a scientific basis for welfare assessment. Weighting factors that represent the relative importance of the attributes are derived from the scientific statements about the various welfare performance criteria that have been measured by scientists. The welfare score is calculated as the weighted average score. All information in the decision support system is stored in tables in a relational database such that newly available knowledge and insights can be incorporated to refine the model. The model has been developed in line with several existing models but it differs from these models in that it is the first to provide a formalized procedure to explicate the reasoning steps involved in welfare assessment based on available scientific knowledge. N1 -
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Hauser MD, Pearson H, & Seelig D. (2002). Ontogeny of tool use in cottontop tamarins, Saguinus oedipus: innate recognition of functionally relevant features. Anim. Behav., 64, 299.
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Hauser MD, Santos LR, Spaepen GM, & Pearson HE. (2002). Problem solving, inhibition and domain-specific experience: experiments on cotton-top tamarins, Saguinus oedipus. Anim. Behav., 64, 387.
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Miklósi, Á. (2002). Cecilia Heyes and Ludwig Huber (eds): The Evolution of Cognition. Anim. Cogn., 5(3), 187–189.
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Byrne, R. (2002). When cognitive psychology met Japanese primatology. Anim. Cogn., 5(1), 59–60.
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Miklósi, Á. (2002). On the usefulness and limits of functional analogies. Anim. Cogn., 5(1), 17–18.
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Kaplan, G., & Rogers, L. J. (2002). Patterns of Gazing in Orangutans (Pongo pygmaeus). Int. J. Primatol., 23(3), 501–526.
Abstract: Eyes play an important role in communication amongst humans and animals. However, relatively little is known about specific differences in eye morphology amongst primates and how these features might be associated with social structure and direction of gaze. We present a detailed study of gazing and eye morphology-exposed sclera and surrounding features in orangutans. We measured gazing in rehabilitating orangutans in two contexts: interspecific viewing of the experimenter (with video camera) and intraspecific gazing (between subjects). Our findings show that direct staring is avoided and social looking is limited to certain age/social categories: juveniles engage in more looking at other orangutans than do adults or infants. While orangutans use eye movements in social communication, they avoid the more prolonged mutual gaze that is characteristic of humans, and also apparent in chimpanzees and gorillas. Detailed frame-by-frame analysis of videotapes from field and zoo studies of orangutans revealed that they pay visual attention to both human observers and conspecifics by glancing sideways, with the head turned at an angle away from the subject being observed. Mutual gaze was extremely rare, and we have observed only two incidences of gaze following. Orangutans in captivity appear to use a more restricted pattern of gazes compared to free-living, rehabilitating ones, possibly suggesting the presence of a pathological condition (such as depression) in the captive subjects. Our findings have implications for further investigations of social communication and cognition in orangutans.
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