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Schneider, G., & Krueger, K. (2012). Third-party interventions keep social partners from exchanging affiliative interactions with others. Anim. Behav., 83(2), 377–387.
Abstract: Third-party interventions are defined as the interruption of dyadic interactions by third animals through direct physical contact, interposing or threats. Previous studies focused on the analysis of interventions against agonistic encounters. However, there have been no evaluations of interventions against affiliative behaviours, particularly in relation to the intervening animal�s social relationships and its social and spatial position. Horses, Equus caballus, are an interesting model species, as interventions against affiliative interactions occur more frequently than against agonistic interactions. In this study, 64 feral horses displayed 67 interventions in affiliative interactions and eight interventions in agonistic interactions within the observation period. We analysed the interventions in affiliative encounters, and found that it was mainly higher-ranking females that intervened in the affiliative interactions of group mates in the stable horse harems. The intervening animals took an active part in affiliative and agonistic encounters within the group, but did not occupy particular social roles or spatial positions. They intervened in affiliative interactions in which group mates with which they had social bonds interacted with other members of the group. They targeted the nonbonded animal and approached the one with which they were socially bonded. We suggest some species use third-party interventions in affiliative interactions to prevent competition for preferred social interaction partners from escalating into more costly agonistic encounters.
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Palme, R., Touma, C., Arias, N., Dominchin, M. F., & Lepschy, M. (2012). Steroid extraction: Get the best out of faecal samples. Vet. Med. Austria, 100, 238–246.
Abstract: Faecal steroid hormone metabolites are becoming increasingly popular as parameters for reproductive functions and stress. Theextraction of the steroids from the faecal matrix represents the initial step before quantification can be performed. The steroid metabolites present in the faecal matrix are of varying polarity and composition, so selection of a proper extraction procedure is essential. There have been some studies to address this complex but often neglected point. Radiolabelled
steroids (e.g. cortisol or progesterone) have frequently been added to faecal samples to estimate the efficiency of the extraction procedures used. However, native, unmetabolized steroids are normally not present in the faeces and therefore the results are artificial and do not accurately reflect the actual recoveries of the substances of interest. In this respect, recovery experiments based on faecal samples from radiometabolism studies are more informative. In these samples, the metabolite content accurately reflects the mixture of metabolites present in the given species. As a result, it is possible to evaluate different extraction methods for use with faecal samples. We present studies on sheep, horses, pigs, hares and dogs that utilized samples containing naturally metabolized, 14C-labelled steroids.
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Heyes, C. (2012). What's social about social learning? J Comp Psychol, 120.
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Smaers, J. B., Dechmann, D. K. N., Goswami, A., Soligo, C., & Safi, K. (2012). Comparative analyses of evolutionary rates reveal different pathways to encephalization in bats, carnivorans, and primates. Proc Natl Acad Sci U S A, 109.
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Benson-Amram, S., & Holekamp, K. E. (2012). Innovative problem solving by wild spotted hyenas. Proc R Soc B, 279, 4087–4095.
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Thornton, A., & Samson, J. (2012). Innovative problem solving in wild meerkats. Anim Behav, 83.
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Briefer, E. F., Padilla de la Torre, M., & McElligott, A. G. (2012). Mother goats do not forget their kids' calls. Proc R Soc B, 279.
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Van Horik, J., Clayton, N., & Emery, N. (2012). Convergent evolution of cognition in Corvids, Apes and other animals. In J. Vonk, & T. Shackelford (Eds.), Oxford Handbook of Comparative Evolutionary Psychology. New York: Oxford University Press.
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Tennie, C., Call, J., & Tomasello, M. (2012). Untrained chimpanzees (Pan troglodytes schweinfurthii) fail to imitate novel actions. PLoS One, 7.
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Van Schaik, C. P., Isler, K., & Burkart, J. M. (2012). Explaining brain size variation: from social to cultural brain. Trends Ecol Evol, 16.
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