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Byrne, R. W., & Russon, A. E. (1998). Learning by imitation: a hierachical approach. Behav. Brain Sci., 21, 667–721.
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Hopkins, W. D., & Parr, L. A. (1998). Lateralized behavior and lymphocyte counts in chimpanzees (pan troglodytes): A cross-sectional and longitudinal assessment. Developmental Neuropsychology, 14(4), 519–533.
Abstract: Cross?sectional and longitudinal assessment of lymphocyte count and behavioral laterality was examined in a sample of captive chimpanzees (Pan troglodytes) to assess the validity of the Geschwind?Behan?Galaburda (GBG) theory of cerebral lateralization. For the cross?sectional analysis, chimpanzees classified as right?handed for feeding exhibited lower lymphocyte counts than chimpanzees classified as either ambiguously handed or left?handed. Longitudinal analysis indicated that some measures of laterality within the first 3 months of life predicted (a) direction of hand preference at 2 to 5 years of age and (b) lymphocyte counts for the first 3 years of life. The association between lymphocyte count and behavioral laterality was more evident in males than females. Taken together, the results support some aspects of the GBG theory.
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Alexander, S. L., & Irvine, C. H. (1998). The effect of social stress on adrenal axis activity in horses: the importance of monitoring corticosteroid-binding globulin capacity. Journal of Endocrinology, 157(3), 425–432.
Abstract: Plasma cortisol is largely bound to corticosteroid-binding globulin (CBG), which regulates its bioavailability by restricting exit from capillaries. Levels of CBG may be altered by several factors including stress and this can influence the amount of cortisol reaching cells. This study investigated the effect of social instability on plasma concentrations of CBG, total and free (not protein bound) cortisol in horses. Horses new to our research herd ('newcomers') were confined in a small yard with four dominant resident horses for 3-4 h daily for 3-4 (n = 5) or 9-14 (n = 3) days. Jugular blood was collected in the mornings from newcomers before the period of stress began ('pre-stress'), and then before each day's stress. Residents were bled before stress on the first and thirteenth day. Residents always behaved aggressively towards newcomers. By the end of the stress period, all newcomers were subordinate to residents. In newcomers (n = 8) after 3-4 days of social stress, CBG binding capacity had fallen (P = 0.0025), while free cortisol concentrations had risen (P = 0.0016) from pre-stress values. In contrast, total cortisol did not change. In residents, CBG had decreased slightly but significantly (P = 0.0162) after 12 days of stress. Residents and newcomers did not differ in pre-stress CBG binding capacity, total or free cortisol concentrations. However, by the second week of stress, CBG binding capacity was lower (P = 0.015) and free cortisol higher (P = 0.030) in newcomers (n = 3) than in residents. Total cortisol did not differ between the groups. In conclusion social stress clearly affected the adrenal axis of subordinate newcomer horses, lowering the binding capacity of CBG and raising free cortisol concentrations. However, no effect of stress could be detected when only total cortisol was measured. Therefore, to assess adrenal axis status accurately in horses, it is essential to monitor the binding capacity of CBG and free cortisol concentrations in addition to total cortisol levels.
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Vetvik, H., Grewal, H. M. S., Haugen, I. L., Åhrén, C., & Haneberg, B. (1998). Mucosal antibodies can be measured in air-dried samples of saliva and feces. Journal of Immunological Methods, 215(1–2), 163–172.
Abstract: IgA antibodies reflecting airways or intestinal mucosal immune responses can be found in saliva and feces, respectively, and IgG antibodies reflecting serum antibodies can be found in saliva. In this study, antibodies were detected in samples of saliva and feces which had been air-dried at room temperature (+20°C) or +37°C, and stored at these temperatures for up to 6 months. In saliva the antibody levels increased, while the antibodies in feces decreased upon storage. The individual IgA antibody concentrations which were adjusted by using the ratios of specific IgA/total IgA were relatively stable in both saliva and feces, and correlated with corresponding antibody levels in samples which had been stored at -20°C. The results indicate that air-dried saliva and feces can be used for semiquantitative measurements of mucosal antibodies, even after prolonged storage at high temperatures and lack of refrigeration.
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Daniel, J. C., & Mikulka, P. J. (1998). Discrimination learning in the white rhinoceros. Appl. Anim. Behav. Sci., 58(1–2), 197–202.
Abstract: This study examined the ability of two adult white rhinoceroses (Ceratotherium simum simum) to develop a visual discrimination between an open circle and a triangle. These stimuli were presented as black symbols on large white cards. The cards were presented 4.6 m apart and a food reward was given if the subject approached the open circle. Ten discrimination choices were given daily until each subject reached the criterion of 80% correct responding over a block of 50 trials. The female reached the criterion over trials 151–200, while the male required considerably longer (trials 501–550). The male's discrimination was dramatically affected by a shift in the food reward. This study demonstrates that these rhinos were able to develop a successful discrimination and this protocol could be used to further examine their visual acuity.
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Klingel, H. (1998). Observations on social organization and behaviour of African and Asiatic Wild Asses (Equus africanus and Equus hemionus). Appl Anim Behav Sci, 60(2), 103–113.
Abstract: 1This paper appears with kind permission of Verlag Paul Parey, Berlin and Hamburg. It was originally published in Z. Tierpsychol., 44, 323-331 (1977), ISSN 0044-3573/ASTM-Coden: ZETIAG.1
Abstract
African and Asiatic Wild Asses (Equus africanus and Equus hemionus) live in unstable groups or herds of variable composition. Some of the adult stallions are territorial in large territories in which they tolerate other ♂♂. The territorial ♂♂ are dominant over all their conspecifics
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Mench, J. A., Morrow-Tesch, J., & Chu, L. - R. (1998). Environmental enrichment for farm animals. Lab Anim., 27, 32–36.
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Nissen, J. (1998). Enzyklopädie der Pferderassen. Stuttgart: Kosmos.
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Dyer, F. C. (1998). Spatial Cognition: Lessons from Central-place Foraging Insects. In Russell P. Balda, Irene M. Pepperberg, & Alan C. Kamil (Eds.), Animal Cognition in Nature (pp. 119–154). London: Academic Press.
Abstract: Summary Spatial orientation has played an extremely important role in the development of ideas about the behavioral capacities of animals. Indeed, as the modern scientific study of animal behavior emerged from its roots in zoology and experimental psychology, studies of spatial orientation figured in the work of many of the pioneering researchers, including Tinbergen (), von ), Watson () and .
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Smith, W. J. (1998). Cognitive Implications of an Information-sharing Model of Animal Communication. In Russell P. Balda, Irene M. Pepperberg, & Alan C. Kamil (Eds.), Animal Cognition in Nature (pp. 227–243). London: Academic Press.
Abstract: Summary In social communication, one animal signals and another responds. Several cognitive steps are involved as the second animal selects its responses; these steps can be described as follows in terms of an informational model. First, the responding individual must evaluate the information made available by the signaling on the basis of other information, available from sources contextual to the signal. Second, the respondent must fit all of the relevant information into patterns generated from recall of past events (conscious recall is not generally required; pattern fitting is a fundamental skill). Third, conditional predictions must be made; and fourth, the individual must test and modify any of these predictions for which significant consequences exist. Many vertebrate animals appear to respond to signaling with considerable flexibility. Communicative events are thus complex but are by no means intractable. Indeed, communication provides us with excellent opportunities to investigate animal cognition.
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