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Cameron, E. Z.,, Linklater, W. L.,, Stafford, K. J.,, & Minot, E. O.,. (2003). Social grouping and maternal behaviour in feral horses (Equus caballus): the influence of males on maternal protectiveness. Behav. Ecol. Sociobiol., 53(2), 92–101.
Abstract: The risk of infant injury or mortality influences maternal behaviour, particularly protectiveness. Mares are found in bands with a single stallion or bands with more than one stallion in which paternity is less certain. We investigated maternal behaviour in relation to band type. Mares in bands with more than one stallion were more protective of their foals, particularly when stallions and foals approached one another. The rate of aggression between the stallion and foal was a significant predictor of maternal protectiveness, and mare protectiveness was significantly correlated with reduced reproductive success in the subsequent year. Mares that changed band types with a foal at foot, or had their band type experimentally altered, were more protective of their foal in multi-stallion bands than they were in single-stallion bands. Equids are unusual amongst ungulates in that infanticide and feticide have been reported. Both occur where paternity has been uncertain, and equid social structure is similar to other species in which infanticide has been reported. Stallions benefit from infanticide as the mare has greater reproductive success in the subsequent year. Stallion aggression is a significant modifier of mare behaviour and maternal effort, probably due to the risk of infanticide.
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RHO, J. R., SRYGLEY, R. B., & CHOE, J. C. (2004). Behavioral ecology of the Jeju pony (Equus caballus): Effects of maternal age, maternal dominance hierarchy and foal age on mare aggression. Ecol. Res., 19(1), 55–63.
Abstract: On Jeju Island, Korea, dominance hierarchy and maternal care according to maternal age were studied in a herd of Jeju ponies (Equus caballus), consisting of 73 mares, their foals and one stallion. Dominance ranks were nearly linear and increased significantly with the age of mares. Most aggressive encounters involved mares under 5 years old. Mares under the age of 5 years have apparently not established their rank. The mean frequency of aggressive actions of mares per hour increased significantly as the day of parturition approached. Aggressive actions of mares with foals decreased significantly as their foals aged. The overall frequency of aggression of mares with foals also decreased significantly with the age of the mares. Our results suggest that the cost of maternal care is lower for older, more dominant mares than for subordinate ones.
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Miller, G. (2006). Animal behavior. Signs of empathy seen in mice. Science, 312(5782), 1860–1861.
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Miklósi, Á., & Soproni, K. (2006). A comparative analysis of animals' understanding of the human pointing gesture. Anim. Cogn., 9(2), 81–93.
Abstract: We review studies demonstrating the ability of some animals to understand the human pointing gesture. We present a 3-step analysis of the topic. (1) We compare and evaluate current experimental methods (2) We compare available experimental results on performance of different species and investigate the interaction of species differences and other independent variables (3) We evaluate how our present understanding of pointing comprehension answers questions about function, evolution and mechanisms. Recently, a number of different hypotheses have been put forward to account for the presence of this ability in some species and for the lack of such comprehension in others. In our view, there is no convincing evidence for the assumption that the competitive lifestyles of apes would inhibit the utilization of this human gesture. Similarly, domestication as a special evolutionary factor in the case of some species falls short in explaining high levels of pointing comprehension in some non-domestic species. We also disagree with the simplistic view of describing the phenomenon as a simple form of conditioning. We suggest that a more systematic comparative research is needed to understand the emerging communicative representational abilities in animals that provide the background for comprehending the human pointing gesture.
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Seyfarth, R. M., & Cheney, D. L. (2003). The Structure of Social Knowledge in Monkeys. In F. B. M. de Waal, & P. L. Tyack (Eds.), Animal Social Complexity: Intelligence, Culture, and Individualized Societies. Cambridge, Massachusetts: Harvard University Press.
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Hanggi, E. B. (2005). The Thinking Horse: Cognition and Perception. In International Veterinary Information Service (Vol. 51).
Abstract: Cognition and perception in horses has often been misunderstood. Not only in the past but even today, people proclaim that horses react only by instinct, that they are just conditioned-response animals, that they lack advanced cognitive ability, and that they have poor visual capabilities (e.g., acuity, color vision, depth perception). Until relatively recently, there was little scientific evidence to address such beliefs. Change, however, is underway as scientific and public interest in all aspects of equine learning and perception intensifies. A review of the scientific literature, as well as practical experience, shows that horses excel at simpler forms of learning such as classical and operant conditioning, which is not surprising considering their trainability when these principles and practices are applied. Furthermore, horses have shown ease in stimulus generalization and discrimination learning. Most recently and unexpected by many, horses have solved advanced cognitive challenges involving categorization learning and some degree of concept formation. A comprehensive understanding of the cognitive and perceptual abilities of horses is necessary to ensure that this species receives proper training, handling, management, and care.
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Mulcahy, N. J., & Call, J. (2006). Apes save tools for future use. Science, 312(5776), 1038–1040.
Abstract: Planning for future needs, not just current ones, is one of the most formidable human cognitive achievements. Whether this skill is a uniquely human adaptation is a controversial issue. In a study we conducted, bonobos and orangutans selected, transported, and saved appropriate tools above baseline levels to use them 1 hour later (experiment 1). Experiment 2 extended these results to a 14-hour delay between collecting and using the tools. Experiment 3 showed that seeing the apparatus during tool selection was not necessary to succeed. These findings suggest that the precursor skills for planning for the future evolved in great apes before 14 million years ago, when all extant great ape species shared a common ancestor.
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Johnson, D. D. P., Stopka, P., & Knights, S. (2003). Sociology: The puzzle of human cooperation. Nature, 421(6926), 911–2; discussion 912.
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Feh, C. (1999). Alliances and reproductive success in Camargue stallions. Anim. Behav., 57(3), 705–713.
Abstract: A study of a herd of Camargue horsesEquus caballus, showed that while the majority of high-ranking stallions held single-male harems, some sons of low-ranking mares, being low ranking themselves, formed alliances that could last a lifetime. The two stallions were each other's closest associate and preferential grooming partner. Alliances were based on coalitions in which either both partners confronted an intruder synchronously or the dominant of the pair tended the female(s) while the subordinate simultaneously displayed towards the rival. Alliance partners were of similar age but were not more closely related to each other than to other stallions in the herd. Long-term paternity data revealed that subordinates sired close to a quarter of the foals born into the alliance group, and significantly more foals than low-ranking stallions in the herd adopting a `sneak'-mating strategy. The dominant appeared to benefit from the presence of his subordinate partner. Fights occurred all year round, and the subordinate stallion of each alliance pair fought outside competitors more than twice as often as the dominant. Forming short-term alliances before defending mares on their own may enhance long-term reproductive success for both partners. Other benefits to both partners include higher survivorship of their foals and increased access to proven reproductive mares. These results suggest that the relationship between alliance partners is based on mutualism, but several conditions for reciprocity seem to be fulfilled: the benefit to the dominant (assistance in fights), and the benefit to the subordinate (access to reproduction), are both costly to the other partner and delayed in time.
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Moons, C., Heleski, C. R., Leece, C. M., & Zanella, A. J. (2002). Conflicting Results in the Association Between Plasma and Salivary Cortisol Levels in Foals. Retrieved May 23, 2024, from http://www3.vet.upenn.edu/labs/equinebehavior/hvnwkshp/hv02/zanella.htm
Abstract: Introduction
Glucocorticoids are present in many biological fluids as a free fraction or bound to Corticoid
Binding Globulins (CBG) (Matteri et al, 2000). There are conflicting claims regarding the validity of
saliva as a biological fluid to measure cortisol in horses (Lebelt et al, 1996; McGreevy and Pell, 1998;
van der Kolk et al, 2001). Measuring changes in salivary cortisol levels in normal horses and horses
with Cushing`s disease van der Kolk and collaborators (2001) demonstrated the validity of saliva to
assess adrenal function. Puzzling results were reported by McGreevy and Pell (1998) who suggested
that plasma and salivary cortisol concentrations in horses showing oral stereotypies were correlated
but this association was non-existent in control animals. Investigating the responses of foals to
branding and foot-trimming Zanella et al (unpublished results) were unable to identify a relationship
between plasma and salivary cortisol levels in foals. In several species, levels of cortisol in plasma and
saliva are tightly correlated (Fenske, 1996). Cortisol found in blood consists of a fraction bound to
corticoid binding globulin (CBG) and a free, unbound fraction. Free cortisol represents the
biologically active fraction of this steroid hormone. Salivary cortisol reflects the unbound fraction
found in plasma or serum and it passes readily through the parotid membrane (Riad-Fahmy, 1983;
Horning Walker et al,1977). Unbound steroids transfer rapidly between plasma and saliva
(Walker,1989; Scott et al 1990). Saliva flow-rate does not appear to influence saliva cortisol levels in
different species (Hubert and de Jong-Meyer, 1989; Walker 1989, Scott et a, 1990). In horses, Lebelt
et al (1996) reported that salivary and plasma total cortisol in stallions were correlated. We
hypothesized that changes in salivary cortisol in foals would show a pattern that is correlated to that of
plasma free and plasma total cortisol concentrations in foals. In addition, we anticipated that the lack
of good sampling techniques provides an explanation for the failure in determining the association
between salivary and plasma cortisol in foals.
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