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Saayman, G. S. (1971). Behaviour of the adult males in a troop of free-ranging Chacma baboons (Papio ursinus). Folia Primatol (Basel), 15(1), 36–57.
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Roth II, T. C., Cox, J. G., & Lima, S. L. (2008). The Use and Transfer of Information About Predation Risk in Flocks of Wintering Finches. Ethology, 114(12), 1218–1226.
Abstract: ABSTRACT
Several studies in behavior have focused in some way on how groups of prey gather and use information about predation risk. Although asymmetries in information about risk exist among members of real groups, we know little about how such uneven information might affect individual or group antipredator decisions. Hence, we studied the use and transfer of information about the risk of predation in small flocks of wintering birds. House finches (Carpodacus mexicanus; 28 groups of three) were held in large enclosures divided into safe and risky patches. We controlled the information about risk available to each individual by conducting attacks with a model hawk that was visible to only a single (informed) bird. Repeated attacks on a single individual did not reduce the amount of feeding by other birds in that patch, although the time to resume feeding after observing a response to an attack event was somewhat longer than after a no attack event. These results suggest that informed individuals impart some information to naive (uninformed) birds, but this effect was not strong. In fact, the frequent return of informed individuals to feeders after observing uninformed individuals feed suggests that finches relied more on public information regarding safety than their own personal information in deciding when to feed. Group patch choice appeared to be based on a majority-rules decision, although an effect of dominance status was apparent. Our results suggest that subordinate flock members may exert a large influence over group decision-making by acting as spatial 'anchors'.
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Rose-Meierhöfer, S., Standke, K., & Hoffmann, G. (2010). Auswirkungen verschiedener Gruppengrößen auf Bewegungsaktivität, Body Condition Score, Liege- und Sozialverhalten bei Jungpferden. Züchtungskunde, 82(4), 282–291.
Abstract: Ziel der Untersuchung war es, herauszufinden, welche Auswirkungen eine Erhöhung der
Gruppengröße bei Jungpferden auf die Bewegungsaktivität, das Liege- und Sozialverhalten
und die Körperkondition hat. Hierfür wurden insgesamt 42 Pferde im Alter von ein
bis zwei Jahren in Laufstallhaltung in die Untersuchung einbezogen. Die Jungpferde aus
der Bewegungs- und Liegeverhaltensanalyse waren in zwei Kleingruppen (acht und
11 Tiere) und einer Großgruppe (23 Tiere) aufgestallt.
In der Bewegungsaktivität waren deutliche Unterschiede zu erkennen. Es ließ sich ein
positiver Einfluss einer höheren Tierzahl nachweisen, aber kein Einfluss des Alters. Beim
Ruheverhalten konnten höhere Liegezeiten und -frequenzen mit einer Zunahme der
Gruppengröße und eine Abnahme der Liegezeit mit zunehmendem Alter ermittelt werden.
Eine Störung des Liegeverhaltens durch Gruppengrößen, die nicht der natürlichen
Herdenstruktur des Pferdes entsprechen, wurde nicht nachgewiesen. Jedoch hatte die
Haltung der Jährlinge in der großen Gruppe einen Anstieg der repulsiven Verhaltensweisen
zur Konsequenz. Zudem zeigte die Bestimmung des Body Condition Scores
Unterschiede in der Körperkondition bei den Jährlingen der Groß- bzw. der Kleingruppe.
Einem Mangel an Bewegung, der für das Auftreten von Gliedmaßenerkrankungen und
Verhaltensstörungen verantwortlich gemacht wird, kann durch die Haltung von Jungpferden
in großen Gruppen entgegengewirkt werden.
[It is often discussed that the inactivity of horses causes diseases of their musculoskeletal system. Due to these problems the objective of the investigation was to quantify if the size of a group has an effect on the behaviour of young horses. Data from 42 horses in the age of one to two years have been involved in the investigation. The data of two small groups were compared with data of one big group with 23 horses. The movement and lying behaviour of 28 horses were measured with ALT pedometers. The social behaviour of 33 yearlings was documented by direct observation. The results show that the median of the movement time of horses in group A is 82 minutes per day. In group B this increases to a median of 101 and group C reaches the highest median of 149. In the case of lying time an increasing group size leads to a longer duration and a higher frequency of lying, whereas an increase in the age reduces the lying duration. International research studies have shown that keeping of horses in big group husbandry systems is not very common by the owners of horses. In contrast these investigations have shown that horse keeping in big groups has no negative influence on the social behaviour and the Body Condition Score of young horses.]
Keywords: Liegen, Aktivität, Gruppenhaltung, Jungpferde, Sozialverhalten, Body Condition Score [Lying behaviour, activity behaviour, group housing, young horses, social behaviour, Body Condition Score]
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Rosati, A. G. (2017). Foraging Cognition: Reviving the Ecological Intelligence Hypothesis. Trends in Cognitive Sciences, 21(9), 691–702.
Abstract: What are the origins of intelligent behavior? The demands associated with living in complex social groups have been the favored explanation for the evolution of primate cognition in general and human cognition in particular. However, recent comparative research indicates that ecological variation can also shape cognitive abilities. I synthesize the emerging evidence that ?foraging cognition? ? skills used to exploit food resources, including spatial memory, decision-making, and inhibitory control ? varies adaptively across primates. These findings provide a new framework for the evolution of human cognition, given our species? dependence on costly, high-value food resources. Understanding the origins of the human mind will require an integrative theory accounting for how humans are unique in both our sociality and our ecology.
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Romano, N., Vitale, F., Alesi, D. R., Bonura, F., La Licata, R., Intonazzo, V., et al. (1992). The changing pattern of human immunodeficiency virus type 1 infection in intravenous drug users. Results of a six-year seroprevalence study in Palermo, Italy. Am J Epidemiol, 135(11), 1189–1196.
Abstract: A cross-sectional seroepidemiologic study was carried out between 1985 and 1990 in 1,567 heterosexual intravenous drug users who had been seen at the AIDS Regional Reference Center in Palermo, Italy, to evaluate the rate of human immunodeficiency virus type 1 (HIV-1) seroprevalence in this group and its long-term trend. Sixty serum samples collected from drug users in 1980 and 1983, before the founding of the Center (1985), were tested as well. Some demographic and behavioral risk factors were studied in a subgroup of intravenous drug users enrolled in 1985, 1987, and 1990 for their possible association with HIV-1. These factors were also studied in relation to hepatitis B virus infection, since both viruses share the same modes of spread. These drug users had a higher prevalence of markers for hepatitis B virus than of HIV-1 antibodies, and the prevalence rates in sera collected declined over time for both infections. The presence of both antibodies to HIV-1 and markers for hepatitis B virus was independently associated with the age of the drug user, the duration of drug use, and the year of serum collection. Antibodies to HIV-1 were observed more frequently in females than in males. No relation was found between education or employment status and the presence of HIV-1 antibodies or hepatitis B virus markers. Although new HIV-1 infections still occur, the decline in seroprevalence observed at the end of the 1980s might be related to modifications in social behavior among newer drug users, partial exhaustion of the susceptible population, and increasing risk awareness in more experienced users.
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Romanes G.J. (1882). Animal Intelligence. New York: Appleton.
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Rizzolatti, G., Fogassi, L., & Gallese, V. (2006). Mirrors of the mind. Sci Am, 295(5), 54–61.
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Rizzolatti, G., Fogassi, L., & Gallese, V. (2001). Neurophysiological mechanisms underlying the understanding and imitation of action. Nat Rev Neurosci, 2(9), 661–670.
Abstract: What are the neural bases of action understanding? Although this capacity could merely involve visual analysis of the action, it has been argued that we actually map this visual information onto its motor representation in our nervous system. Here we discuss evidence for the existence of a system, the ‘mirror system’, that seems to serve this mapping function in primates and humans, and explore its implications for the understanding and imitation of action.
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Ripple, W. J., Estes, J. A., Beschta, R. L., Wilmers, C. C., Ritchie, E. G., & Hebblewhite, M. (2014). Status and ecological effects of the world's largest carnivores. Science, 343.
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Rietbroek, N. J., Dingboom, E. G., Joosten, B. J. L. J., Eizema, K., & Everts, M. E. (2007). Effect of show jumping training on the development of locomotory muscle in young horses. Am J Vet Res, 68(11), 1232–1238.
Abstract: OBJECTIVE: To investigate whether training for show jumping that is commenced early after birth affects the characteristics of equine locomotory muscle. ANIMALS: 19 Dutch Warmblood horses. PROCEDURES: Horses were assigned to a trained or not trained (control) group. After weaning, training (free jumping [2 d/wk] that was alternated with a 20-minute period of exercise in a mechanical rotating walker [3 d/wk]) was started and continued until horses were 3 years old. Fiber type composition (determined from myosin heavy chain [MyHC] content), fiber area, diffusion index (area supplied by 1 capillary), citrate synthase activity, and Na(+),K(+)-ATPase content were assessed in gluteus medius muscle specimens collected at 0.5, 1, 2, and 3 years. RESULTS: Developmental changes included an increase in MyHC fiber type IIa and a decrease in type IIad; increases in fiber area, diffusion index, and citrate synthase activity; and a decrease in Na(+),K(+)-ATPase content. The MyHC fiber type I and type IId were detected in high and low proportions, respectively. Training increased Na(+),K(+)-ATPase content, but did not affect other variables. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, show jumping training at an early age resulted in increased Na(+),K(+)-ATPase content of the deep portions of the gluteus medius muscle. The lack of training effects on the other muscle characteristics can partly be explained by the fact that an appropriate (aerobic) fiber type composition was already established at training commencement. These data also suggested that the developmental changes in equine muscle represent sufficient adaptation to meet the demands of this specific training.
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