König von Borstel, U., Euent, S., Graf, P., König, S., & Gauly, M. (2011). Equine behaviour and heart rate in temperament tests with or without rider or handler. Physiol. Behav., 104(3), 454–463.
Abstract: The aim of the present study was to compare horses' heart rate (HR), heart rate variability (RMSSD, pNN50) and behaviour in the same temperament test when being ridden, led, and released free. Behavioural measurements included scores and linear measurements for reactivity (R), activity (A), time to calm down (T) and emotionality (E), recorded during the approach (1) and/or during confrontation with the stimulus (2). Sixty-five horses were each confronted 3 times (1 ridden, 1 led, 1 free running in balanced order) with 3 novel and/or sudden stimuli. Mixed model analysis indicated that leading resulted in the lowest (P < 0.05 throughout) reactions as measured by A1, A2, E1, E2, R2, and pNN50 while riding produced the strongest (A1, T2, HR, RMSSD, pNN50) or medium (E1, E2, R2) reactions. Free running resulted either in the strongest (A2, E1, E2, R2) or in the lowest (A1, T2, HR, RMSSD, pNN50) reactions. The repeatability across tests for HR (0.57), but not for RMSSD (0.23) or pNN50 (0.25) was higher than for any behavioural measurement: the latter ranged from values below 0.10 (A1, A2, T2) to values between 0.30 and 0.45 (E1, E2, R2). Overall, the results show that a rider or handler influences, but not completely masks, the horses' intrinsic behaviour in a temperament test, and this influence appeared to be stronger on behavioural variables and heart rate variability than on the horses' heart rates. Taking both practical considerations and repeatabilities into account, reactivity appears to be the most valuable parameter. Emotionality and heart rate can also yield valid results reflecting additional dimensions of temperament although their practical relevance may be less obvious. If a combination of observed variables is chosen with care, a valid assessment of a horse's temperament may be possible in all types of tests. However, in practice, tests that resemble the practical circumstances most closely, i.e. testing riding horses under a rider, should be chosen.
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Sankey, C., Henry, S., Clouard, C., Richard-Yris, M. - A., & Hausberger, M. (2011). Asymmetry of behavioral responses to a human approach in young naive vs. trained horses. Physiology & Behavior, 104(3), 464–468.
Abstract: The aim of this study was to investigate the impact of training experience on young horses (Equus caballus)’ lateralized responses to an approaching human. The results show that the one year old untrained horses display asymmetrical responses to an approaching human, with more negative reactions (escapes, threats) when approached from the left side, while approaches towards the right shoulder elicited more positive behaviors. On the contrary, two years old trained horses reacted equally positively to approaches and contact on both sides. Our findings support those of previous studies investigating a link between emotionality and laterality and confirm the role of the left hemisphere in the processing of novel or negative stimuli. Moreover, the data underline the impact work and training can have on this laterality in horses.
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Zaine, L., Ferreira, C., de O. S. Gomes, M., Monti, M., Tortola, L., Vasconcellos, R. S., et al. (2011). Faecal IgA concentration is influenced by age in dogs. British Journal of Nutrition, 106(Supplement S1), S183–S186.
Abstract: Data comparing age-related alterations in faecal IgA concentrations of dogs are not available in the literature. The present study aimed to
compare the faecal concentrations of IgA in puppies, mature and senior dogs. A total of twenty-four beagle dogs were used, including
eight puppies (5 months old, four females and four males), eight mature (4·6 years old, eight males) and eight senior dogs (10·6 years
old, three males and five females). Fresh faecal samples were collected from each dog for three consecutive days and pooled by
animal. After saline extraction, IgA content was measured by ELISA. Data were analysed by one-way ANOVA, and means were compared
with Tukey’s test (P,0·05). Results showed that puppies have lower faecal IgA concentrations than mature dogs (P,0·05); senior animals
presented intermediary results. The reduced faecal IgA concentration in puppies is consistent with the reduced serum and salivary IgA
concentrations reported previously, suggesting a reduced mucosal immunity in this age group. Although some studies have found an
increased serum IgA concentration in older dogs, this may differ from the intestinal secretion of IgA, which appears to be lower in
some senior animals (four of the eight dogs studied).
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Young, H. P. (2011). The dynamics of social innovation. Proc. Natl. Acad. Sci. U.S.A., 108(Supplement 4), 21285–21291.
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Gorodnichenko, Y., & Roland, G. (2011). Individualism, innovation, and long-run growth. Proc. Natl. Acad. Sci. U.S.A., 108(Supplement 4), 21316–21319.
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Pruvost, M., Bellone, R., Benecke, N., Sandoval-Castellanos, E., Cieslak, M., Kuznetsova, T., et al. (2011). Genotypes of predomestic horses match phenotypes painted in Paleolithic works of cave art. Proceedings of the National Academy of Sciences, 108(46), 18626–18630.
Abstract: Archaeologists often argue whether Paleolithic works of art, cave paintings in particular, constitute reflections of the natural environment of humans at the time. They also debate the extent to which these paintings actually contain creative artistic expression, reflect the phenotypic variation of the surrounding environment, or focus on rare phenotypes. The famous paintings “The Dappled Horses of Pech-Merle,” depicting spotted horses on the walls of a cave in Pech-Merle, France, date back ~25,000 y, but the coat pattern portrayed in these paintings is remarkably similar to a pattern known as “leopard” in modern horses. We have genotyped nine coat-color loci in 31 predomestic horses from Siberia, Eastern and Western Europe, and the Iberian Peninsula. Eighteen horses had bay coat color, seven were black, and six shared an allele associated with the leopard complex spotting (LP), representing the only spotted phenotype that has been discovered in wild, predomestic horses thus far. LP was detected in four Pleistocene and two Copper Age samples from Western and Eastern Europe, respectively. In contrast, this phenotype was absent from predomestic Siberian horses. Thus, all horse color phenotypes that seem to be distinguishable in cave paintings have now been found to exist in prehistoric horse populations, suggesting that cave paintings of this species represent remarkably realistic depictions of the animals shown. This finding lends support to hypotheses arguing that cave paintings might have contained less of a symbolic or transcendental connotation than often assumed.
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Morand-Ferron, J., & Quinn, J. L. (2011). Larger groups of passerines are more efficient problem solvers in the wild. Proc Natl Acad Sci USA, 108(38), 15898–15903.
Abstract: Group living commonly helps organisms face challenging environmental conditions. Although a known phenomenon in humans, recent findings suggest that a benefit of group living in animals generally might be increased innovative problem-solving efficiency. This benefit has never been demonstrated in a natural context, however, and the mechanisms underlying improved efficiency are largely unknown. We examined the problem-solving performance of great and blue tits at automated devices and found that efficiency increased with flock size. This relationship held when restricting the analysis to naive individuals, demonstrating that larger groups increased innovation efficiency. In addition to this effect of naive flock size, the presence of at least one experienced bird increased the frequency of solving, and larger flocks were more likely to contain experienced birds. These findings provide empirical evidence for the “pool of competence” hypothesis in nonhuman animals. The probability of success also differed consistently between individuals, a necessary condition for the pool of competence hypothesis. Solvers had a higher probability of success when foraging with a larger number of companions and when using devices located near rather than further from protective tree cover, suggesting a role for reduced predation risk on problem-solving efficiency. In contrast to traditional group living theory, individuals joining larger flocks benefited from a higher seed intake, suggesting that group living facilitated exploitation of a novel food source through improved problem-solving efficiency. Together our results suggest that both ecological and social factors, through reduced predation risk and increased pool of competence, mediate innovation in natural populations.
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Dochtermann, N. A., & Jenkins, S. H. (2011). Multivariate Methods and Small Sample Sizes. Ethology, 117(2), 95–101.
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Huang, S. - P., Yang, S. - Y., & Hsu, Y. (2011). Persistence of Winner and Loser Effects Depends on the Behaviour Measured. Ethology, 117(2), 171–180.
Abstract: Abstract Recent contest experience can influence an individual’s behaviour in subsequent contests. When the probability of winning a subsequent contest is used to quantify experience effects, a loser effect usually lasts longer than a winner effect. This conclusion, however, may be caused by this probability understating the persistence of the influence of a winning experience on contest decisions. Using Kryptolebias marmoratus, a mangrove killifish, as the study organism, we investigated whether different conclusions about the relative persistence of winning and losing experiences would be reached when different aspects of contest behaviour (probability of initiating attacks, probability of winning non-escalated and escalated contests, escalation rate and contest duration) were measured. The results indicated that the apparent persistence of the effect of winning or losing experiences varied with the behaviour studied. When the likelihood to initiate attacks was used, no winner effect was detected while the loser effect lasted for <1 d. When escalation rate was used, the winner effect lasted for 2–4 d, while the loser effect lasted for 1–2 d. When the probability of winning non-escalated contests was used, the winner effect was detectable for <1 d, while the loser effect lasted for 2–4 d. And, when contest duration was used, the winner effect was detectable for 2–4 d, but no loser effect was detectable. These results show that (1) the probability of winning a subsequent contest understated the persistence of the influence of a winning experience on the fish’s contest decisions, (2) the measures most effective at detecting winner effects are different from those most effective at detecting loser effects and (3) in K. marmoratus, both effects can be detected 2 d after the completion of experience training but both dissipate in 4 d.
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Mersmann, D., Tomasello, M., Call, J., Kaminski, J., & Taborsky, M. (2011). Simple Mechanisms Can Explain Social Learning in Domestic Dogs (Canis familiaris). Ethology, 117(8), 675–690.
Abstract: Abstract Recent studies have suggested that domestic dogs (Canis familiaris) engage in highly complex forms of social learning. Here, we critically assess the potential mechanisms underlying social learning in dogs using two problem-solving tasks. In a classical detour task, the test dogs benefited from observing a demonstrator walking around a fence to obtain a reward. However, even inexperienced dogs did not show a preference for passing the fence at the same end as the demonstrator. Furthermore, dogs did not need to observe a complete demonstration by a human demonstrator to pass the task. Instead, they were just as successful in solving the problem after seeing a partial demonstration by an object passing by at the end of the fence. In contrast to earlier findings, our results suggest that stimulus enhancement (or affordance learning) might be a powerful social learning mechanism used by dogs to solve such detour problems. In the second task, we examined whether naïve dogs copy actions to solve an instrumental problem. After controlling for stimulus enhancement and other forms of social influence (e.g. social facilitation and observational conditioning), we found that dogs’ problem solving was not influenced by witnessing a skilful demonstrator (either an unknown human, a conspecific or the dog’s owner). Together, these results add to evidence suggesting that social learning may often be explained by relatively simple (but powerful) mechanisms.
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