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Whiten, A. (1998). Imitation of the sequential structure of actions by chimpanzees (Pan troglodytes). J Comp Psychol, 112(3), 270–281.
Abstract: Imitation was studied experimentally by allowing chimpanzees (Pan troglodytes) to observe alternative patterns of actions for opening a specially designed “artificial fruit.” Like problematic foods primates deal with naturally, with the test fruit several defenses had to be removed to gain access to an edible core, but the sequential order and method of defense removal could be systematically varied. Each subject repeatedly observed 1 of 2 alternative techniques for removing each defense and 1 of 2 alternative sequential patterns of defense removal. Imitation of sequential organization emerged after repeated cycles of demonstration and attempts at opening the fruit. Imitation in chimpanzees may thus have some power to produce cultural convergence, counter to the supposition that individual learning processes corrupt copied actions. Imitation of sequential organization was accompanied by imitation of some aspects of the techniques that made up the sequence.
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Galef, B. G. J. R., & White, D. J. (1998). Mate-choice copying in Japanese quail, Coturnix coturnix japonica. Anim. Behav., 55(3), 545–552.
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Aronson, L. (1998). Animal behavior case of the month. Aggression directed toward other horses. J Am Vet Med Assoc, 213(3), 358–359.
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Johnsson, J. I., & Akerman, A. (1998). Watch and learn: preview of the fighting ability of opponents alters contest behaviour in rainbow trout. Anim. Behav., 56(3), 771–776.
Abstract: The costs associated with initial conflicts could be reduced if animals can assess the fighting ability of possible future opponents by watching their contest success against other individuals. We tested this hypothesis by conducting repeated dyadic dominance trials on size-matched juvenile rainbow trout,Oncorhynchus mykiss. In the first trial a dyadic contest was `observed' by a single fish separated by a transparent divider. In the second trial, the observer was paired against either the `familiar' dominant fish or an unfamiliar dominant fish from the first trial. We predicted that observers should settle conflicts with previewed opponents faster and with less aggression than those with unfamiliar fish. This prediction was supported for observers that lost against a previewed competitor, since these fish reduced their aggression more rapidly than did unfamiliar observers. Familiar observers that won, however, showed a more rapid increase in aggression compared with unfamiliar winning observers. This suggests that, regardless of whether an observer challenges the initial dominant, this `decision' is taken more rapidly in conflicts with preassessed contestants, because of the a priori information about their fighting ability. Since preassessment could save energy and allow effort to be concentrated on contests with a high payoff/probability of winning, selection may favour preview strategies when contest competition over resources is important for fitness.
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Penn, D., & Potts, W. K. (1998). Untrained mice discriminate MHC-determined odors. Physiol. Behav., 64(3), 235–243.
Abstract: PENN, D. AND W. K. POTTS. Untrained mice distinguish MHC-determined odors. PHYSIOL BEHAV 64(3) 235-243, 1998.--Immune recognition occurs when foreign antigens are presented to T-lymphocytes by molecules encoded by the highly polymorphic genes of the major histocompatibility complex (MHC). House mice (Mus musculus) prefer to mate with individuals that have dissimilar MHC genes. Numerous studies indicate that mice recognize MHC identity through chemosensory cues; however, it is unclear whether odor is determined by classical, antigen-presenting MHC loci or closely linked genes. Previous studies have relied on training laboratory mice and rats to distinguish MHC-associated odors, but there are several reasons why training experiments may be inappropriate assays for testing if MHC genes affect odor. The aim of this study was to determine whether classical MHC genes affect individual odors and whether wild-derived mice can detect MHC-associated odors without training. In the first experiment, we found that wild-derived mice can be trained in a Y-maze to detect the odors of mice that differ genetically only in the MHC region. In the second and third experiments, we used a naturalistic habituation assay and found that wild-derived mice can, without training, distinguish the odors of mice that differ genetically only at one classical MHC locus (dm2 mutants).
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Wanker, R., Apcin, J., Jennerjahn, B., & Waibel, B. (1998). Discrimination of different social companions in spectacled parrotlets ( Forpus conspicillatus ): evidence for individual vocal recognition. Behav. Ecol. Sociobiol., 43(3), 197–202.
Abstract: Abstract: Individual recognition is generally assumed to be a prerequisite for establishing and maintaining a complex social system. Indeed, there is good evidence that highly social species have complex systems of vocal communication with individual recognition by acoustic cues. In this study, we provide experimental evidence that vocal class and individual recognition is present in a non-passerine bird, the spectacled parrotlet (Forpus conspicillatus). Spectacled parrotlets live in a complex system of social relationships. Soon after fledging, the young establish close sibling relationships which are important for successful socialization, pairing and reproduction. In a series of playback experiments we tested if spectacled parrotlets use contact calls for vocal recognition. The results showed that spectacled parrotlets discriminate between the contact calls of different social categories. Adult birds preferred to respond to the contact calls of their mates. Subadult individuals recognized the contact calls of their siblings. During the period of pair bond formation, the affiliative contacts to the siblings decrease, but the parrotlets continue to respond to the calls of their siblings. This is the first evidence that vocal sibling recognition might outlast the period of strong sibling interaction and extends into the period of pair bond formation. In cases of mate loss or divorce, the acoustic contact to their siblings might facilitate the re-establishment of close sibling relationships.
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Potts, R. (1998). Variability selection in hominid evolution. Evol. Anthropol., 7(3), 81–96.
Abstract: Variability selection (abbreviated as VS) is a process considered to link adaptive change to large degrees of environment variability. Its application to hominid evolution is based, in part, on the pronounced rise in environmental remodeling that took place over the past several million years. The VS hypothesis differs from prior views of hominid evolution, which stress the consistent selective effects associated with specific habitats or directional trends (e.g., woodland, savanna expansion, cooling). According to the VS hypothesis, wide fluctuations over time created a growing disparity in adaptive conditions. Inconsistency in selection eventually caused habitat-specific adaptations to be replaced by structures and behaviors responsive to complex environmental change. Key hominid adaptations, in fact, emerged during times of heightened variability. Early bipedality, encephalized brains, and complex human sociality appear to signify a sequence of VS adaptations—i.e., a ratcheting up of versatility and responsiveness to novel environments experienced over the past 6 million years. The adaptive results of VS cannot be extrapolated from selection within a single environmental shift or relatively stable habitat. If some complex traits indeed require disparities in adaptive setting (and relative fitness) in order to evolve, the VS idea counters the prevailing view that adaptive change necessitates long-term, directional consistency in selection. © 1998 Wiley-Liss, Inc.
Keywords: variability selection; hominids; environment; adaptation; natural selection; evolution
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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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Kendrick, K. M. (1998). Intelligent perception. Appl. Anim. Behav. Sci., 57(3-4), 213–231.
Abstract: For an animal from any species to exhibit intelligent perception it must be capable of being consciously aware of what it perceives and capable of learning from this experience. Although many organisms, and for that matter machines, are capable of rapid adaptive learning in response to perception of environmental changes, such adaptations can occur without them being consciously aware either of external stimuli or their response to them. While behavioural and neurophysiological evidence suggests that, apart from ourselves, other higher primates must also be capable of such awareness, an important central question is whether such awareness is a characteristic of primate evolution or if it also occurs in sub-primate mammals as well. In this review I will examine our behavioural and neurophysiological evidence from visual and olfactory recognition studies in the sheep to support the argument that they are likely to be aware of and learn about both social and non-social objects and that they are therefore capable of intelligent perception. However, the impact of motivational changes on these perceptual processes suggests that they may be limited in terms of both prospection and retrospection and dealing with symbolic associations.
Keywords: Intelligent perception; Environmental changes; Primates
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Scheibe, K. M., Schleusner, T., Berger, A., Eichhorn, K., Langbein, J., Dal Zotto, L., et al. (1998). ETHOSYS (R)--new system for recording and analysis of behaviour of free-ranging domestic animals and wildlife. Appl. Anim. Behav. Sci., 55(3-4), 195–211.
Abstract: A storage telemetry system has been developed to monitor domestic animals and wildlife, and has been tested under variable conditions on sheep, Przewalski horse and mouflon. It can be used for automatic recording of different patterns of behaviour, such as activity and feeding, and is based on advanced analysis of sensor-emitted signals. The system is made up of collars (ETHOREC) with sensors and electronic devices for behaviour recording, a central station (ETHOLINK) and software for data transmission and processing (ETHODAT). All components of the ETHOREC recording device are integrated in the collar. Long-time recording of behaviour through up to four different channels and in numerous animals at one and the same time are necessary elements to facilitate biorhythmic analysis of animals under free-ranging conditions. The results obtained from this telemetry system were compared with visual observations on six sheep and four Przewalski horses. Parallel recordings were taken from four sheep, using a recorder for jaw movements. Locomotor activity usually was rated somewhat higher by observers, whereas feed uptake was rated lower. Higher feed uptake values were measured by means of the jaw movement recorder, although deviations thus measured varied less than those noticed by visual observations. All measured series exhibited significant correlations with control values. The system, consequently, was found to be more suitable for determination of diurnal patterns, change over time and relative comparison between behaviour levels than it actually was for measurement of absolute duration of a given behaviour.
Keywords: Telemetry; Diurnal patterns; Activity; Rhythms; Feeding and nutrition
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