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Warmuth, V., Eriksson, A., Bower, M. A., Cañon, J., Cothran, G., Distl, O., et al. (2011). European Domestic Horses Originated in Two Holocene Refugia. PLoS ONE, 6(3), e18194 EP -.
Abstract: <p>The role of European wild horses in horse domestication is poorly understood. While the fossil record for wild horses in Europe prior to horse domestication is scarce, there have been suggestions that wild populations from various European regions might have contributed to the gene pool of domestic horses. To distinguish between regions where domestic populations are mainly descended from local wild stock and those where horses were largely imported, we investigated patterns of genetic diversity in 24 European horse breeds typed at 12 microsatellite loci. The distribution of high levels of genetic diversity in Europe coincides with the distribution of predominantly open landscapes prior to domestication, as suggested by simulation-based vegetation reconstructions, with breeds from Iberia and the Caspian Sea region having significantly higher genetic diversity than breeds from central Europe and the UK, which were largely forested at the time the first domestic horses appear there. Our results suggest that not only the Eastern steppes, but also the Iberian Peninsula provided refugia for wild horses in the Holocene, and that the genetic contribution of these wild populations to local domestic stock may have been considerable. In contrast, the consistently low levels of diversity in central Europe and the UK suggest that domestic horses in these regions largely derive from horses that were imported from the Eastern refugium, the Iberian refugium, or both.</p>
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Lloyd, A. S., Martin, J. E., Bornett-Gauci, H. L. I., & Wilkinson, R. G. (2007). Evaluation of a novel method of horse personality assessment: Rater-agreement and links to behaviour. Appl. Anim. Behav. Sci., 105(1-3), 205–222.
Abstract: The efficacy of questionnaire-based personality assessment has been shown in a variety of animal and human personality studies. There has been a recent increase in questionnaire-based studies focussing on equine personality but with a lack of comparability to studies on other species. The aim of this study was to test the reliability of an assessment method originally developed for primates and demonstrate reliability using three criteria (1) assessments by independent observers must agree with one another, (2) these assessments must predict behaviours and real-world outcomes and (3) observer ratings must be shown to reflect genuine attributes of the individuals rated, not merely the observer's implicit personality theories about how traits co-vary. The personality of 61 horses (Equus caballus) was assessed using a questionnaire constructed of 30 behaviourally defined adjectives (BDAs). Horses were each assessed by three judges, in addition to a total of 2 h behaviour observations recorded per horse. Rater agreement was demonstrated for 72.1% of the horses and 25 of the BDAs. Principal component analysis was carried out on the rating data and revealed six underlying personality components that were labelled “dominance”, “anxiousness”, “excitability”, “protection”, “sociability” and “inquisitiveness”. Component scores for horses were correlated against behavioural observations for the same horses and revealed significant correlations with 20 of the recorded behaviour variables. Correlations between specific components and their associated behaviours were logical and consistent with the types of behaviours that would be expected to be linked with such personality types. The data were shown to meet all three criteria and provided strong evidence that the assessment method was reliably measuring horse personality.
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Burch, J. W., Layne, G. A., Follmann, E. H., & Rexstad, E. A. (2005). Evaluation of Wolf Density Estimation from Radiotelemetry Data. Wildl Soc Bull, 33.
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Fagot, J., & Cook, R. G. (2006). Evidence for large long-term memory capacities in baboons and pigeons and its implications for learning and the evolution of cognition. Proc Natl Acad Sci U S A, 103.
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Hare, J. F., Sealy, S. G., Underwood, T. J., Ellison, K. S., & Stewart, R. L. M. (2003). Evidence of self-referent phenotype matching revisited: airing out the armpit effect. Anim. Cogn., 6(1), 65–68.
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Overli, O., Sorensen, C., Pulman, K. G. T., Pottinger, T. G., Korzan, W., Summers, C. H., et al. (2007). Evolutionary background for stress-coping styles: relationships between physiological, behavioral, and cognitive traits in non-mammalian vertebrates. Neurosci Biobehav Rev, 31(3), 396–412.
Abstract: Reactions to stress vary between individuals, and physiological and behavioral responses tend to be associated in distinct suites of correlated traits, often termed stress-coping styles. In mammals, individuals exhibiting divergent stress-coping styles also appear to exhibit intrinsic differences in cognitive processing. A connection between physiology, behavior, and cognition was also recently demonstrated in strains of rainbow trout (Oncorhynchus mykiss) selected for consistently high or low cortisol responses to stress. The low-responsive (LR) strain display longer retention of a conditioned response, and tend to show proactive behaviors such as enhanced aggression, social dominance, and rapid resumption of feed intake after stress. Differences in brain monoamine neurochemistry have also been reported in these lines. In comparative studies, experiments with the lizard Anolis carolinensis reveal connections between monoaminergic activity in limbic structures, proactive behavior in novel environments, and the establishment of social status via agonistic behavior. Together these observations suggest that within-species diversity of physiological, behavioral and cognitive correlates of stress responsiveness is maintained by natural selection throughout the vertebrate sub-phylum.
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Stuber, G. D., Sparta, D. R., Stamatakis, A. M., van Leeuwen, W. A., Hardjoprajitno, J. E., Cho, S., et al. (2011). Excitatory transmission from the amygdala to nucleus accumbens facilitates reward seeking. Nature, advance online publication.
Abstract: The basolateral amygdala (BLA) has a crucial role in emotional learning irrespective of valence1, 2, 3, 4, 5, 21, 22, 23. The BLA projection to the nucleus accumbens (NAc) is thought to modulate cue-triggered motivated behaviours4, 6, 7, 24, 25, but our understanding of the interaction between these two brain regions has been limited by the inability to manipulate neural-circuit elements of this pathway selectively during behaviour. To circumvent this limitation, we used in vivo optogenetic stimulation or inhibition of glutamatergic fibres from the BLA to the NAc, coupled with intracranial pharmacology and ex vivo electrophysiology. Here we show that optical stimulation of the pathway from the BLA to the NAc in mice reinforces behavioural responding to earn additional optical stimulation of these synaptic inputs. Optical stimulation of these glutamatergic fibres required intra-NAc dopamine D1-type receptor signalling, but not D2-type receptor signalling. Brief optical inhibition of fibres from the BLA to the NAc reduced cue-evoked intake of sucrose, demonstrating an important role of this specific pathway in controlling naturally occurring reward-related behaviour. Moreover, although optical stimulation of glutamatergic fibres from the medial prefrontal cortex to the NAc also elicited reliable excitatory synaptic responses, optical self-stimulation behaviour was not observed by activation of this pathway. These data indicate that whereas the BLA is important for processing both positive and negative affect, the glutamatergic pathway from the BLA to the NAc, in conjunction with dopamine signalling in the NAc, promotes motivated behavioural responding. Thus, optogenetic manipulation of anatomically distinct synaptic inputs to the NAc reveals functionally distinct properties of these inputs in controlling reward-seeking behaviours.
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Powell, G. V. N. (1974). Experimental analysis of the social value of flocking by starlings (Sturnus vulgaris) in relation to predation and foraging. Anim. Behav., 22(2), 501–505.
Abstract: In groups of ten, indidual starlings, Sturnus vulgaris, spent significantly less time in surveillance than did individuals in smaller groups and responded more quickly than single birds to a flying model hawk. Captive starlings in flocks reduce their individual surveillance efforts, but their combined efforts still enable them to be more effective than single birds in the detection of predators. Foraging behaviour of flocks was observed by placing single starlings with groups of tricoloured blackbirds, Agelaius tricolor; the starlings reduced the time they devoted to surveillance at the same rate as if they were with other starlings.
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Mormède, P., Andanson, S., Aupérin, B., Beerda, B., Guémené, D., Malmkvist, J., et al. (2007). Exploration of the hypothalamic-pituitary-adrenal function as a tool to evaluate animal welfare. Physiol. Behav., 92(3), 317–339.
Abstract: Measuring HPA axis activity is the standard approach to the study of stress and welfare in farm animals. Although the reference technique is the use of blood plasma to measure glucocorticoid hormones (cortisol or corticosterone), several alternative methods such as the measurement of corticosteroids in saliva, urine or faeces have been developed to overcome the stress induced by blood sampling itself. In chronic stress situations, as is frequently the case in studies about farm animal welfare, hormonal secretions are usually unchanged but dynamic testing allows the demonstration of functional changes at several levels of the system, including the sensitization of the adrenal cortex to ACTH and the resistance of the axis to feedback inhibition by corticosteroids (dexamethasone suppression test). Beyond these procedural aspects, the main pitfall in the use of HPA axis activity is in the interpretation of experimental data. The large variability of the system has to be taken into consideration, since corticosteroid hormone secretion is usually pulsatile, follows diurnal and seasonal rhythms, is influenced by feed intake and environmental factors such as temperature and humidity, age and physiological state, just to cite the main sources of variation. The corresponding changes reflect the important role of glucocorticoid hormones in a number of basic physiological processes such as energy metabolism and central nervous system functioning. Furthermore, large differences have been found across species, breeds and individuals, which reflect the contribution of genetic factors and environmental influences, especially during development, in HPA axis functioning. Usually, these results will be integrated with data from behavioral observation, production and pathology records in a comprehensive approach of farm animal welfare.
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Meese, G. B., & Ewbank, R. (1973). Exploratory behaviour and leadership in the domesticated pig. Br. Vet. J., 129(3), 251–259.
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