Cozzi, B., Povinelli, M., Ballarin, C., & Granato, A. (2014). The Brain of the Horse: Weight and Cephalization Quotients. Brain Behav Evol, 83(1), 9–16.
Abstract: The horse is a common domestic animal whose anatomy has been studied since the XVI century. However, a modern neuroanatomy of this species does not exist and most of the data utilized in textbooks and reviews derive from single specimens or relatively old literature. Here, we report information on the brain of Equus caballus obtained by sampling 131 horses, including brain weight (as a whole and subdivided into its constituents), encephalization quotient (EQ), and cerebellar quotient (CQ), and comparisons with what is known about other relevant species. The mean weight of the fresh brains in our experimental series was 598.63 g (SEM ± 7.65), with a mean body weight of 514.12 kg (SEM ± 15.42). The EQ was 0.78 and the CQ was 0.841. The data we obtained indicate that the horse possesses a large, convoluted brain, with a weight similar to that of other hoofed species of like mass. However, the shape of the brain, the noteworthy folding of the neocortex, and the peculiar longitudinal distribution of the gyri suggest an evolutionary specificity at least partially separate from that of the Cetartiodactyla (even-toed mammals and cetaceans) with whom Perissodactyla (odd-toed mammals) are often grouped.
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Collins, G. H., Petersen, S. L., Carr, C. A., & Pielstick, L. (2014). Testing VHF/GPS Collar Design and Safety in the Study of Free-Roaming Horses. Plos One, 9(9), e103189.
Abstract: Effective and safe monitoring techniques are needed by U.S. land managers to understand free-roaming horse behavior and habitat use and to aid in making informed management decisions. Global positioning system (GPS) and very high frequency (VHF) radio collars can be used to provide high spatial and temporal resolution information for detecting free-roaming horse movement. GPS and VHF collars are a common tool used in wildlife management, but have rarely been used for free-roaming horse research and monitoring in the United States. The purpose of this study was to evaluate the design, safety, and detachment device on GPS/VHF collars used to collect free-roaming horse location and movement data. Between 2009 and 2010, 28 domestic and feral horses were marked with commercial and custom designed VHF/GPS collars. Individual horses were evaluated for damage caused by the collar placement, and following initial observations, collar design was modified to reduce the potential for injury. After collar modifications, which included the addition of collar length adjustments to both sides of the collar allowing for better alignment of collar and neck shapes, adding foam padding to the custom collars to replicate the commercial collar foam padding, and repositioning the detachment device to reduce wear along the jowl, we observed little to no evidence of collar wear on horses. Neither custom-built nor commercial collars caused injury to study horses, however, most of the custom-built collars failed to collect data. During the evaluation of collar detachment devices, we had an 89% success rate of collar devices detaching correctly. This study showed that free-roaming horses can be safely marked with GPS and/or VHF collars with minimal risk of injury, and that these collars can be a useful tool for monitoring horses without creating a risk to horse health and wellness.
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Giese,, C. Giese, Gerber,, V. Gerber, Howald,, M. Howald, et al. (2014). Stressbelastung und Verhalten von Pferden in stromführenden gegenüber nicht stromführenden Führanlagen. SAT, 156(4), 163–169.
Abstract: Um die Stressbelastung von Pferden in Führanlagen zu vergleichen, wurden 12 Pferde während 3 Wochen in einer Führanlage mit und ohne stromführenden (3.7 kV) Abtrennungen bewegt. Zur Ermittlung der Stressbelastung wurden die Cortisolwerte im Blut gemessen, die Herzschlagfrequenz mittels Polar® registriert und das Verhalten erfasst. Weder die Cortisol- noch die Herzfrequenzmessungen zeigten einen bedeutenden signifikanten Unterschied zwischen Pferden, die in einer stromführenden beziehungsweise nicht stromführenden Führanlage gingen. Die höchsten Cortisol- und Herzfrequenzwerte wurden in der ersten Woche (Angewöhnungsphase) verzeichnet. Signifikante Unterschiede wurden bei den Verhaltensparametern «Spontanes Wechseln des Abteils» und «Kontakt mit der Trennwand» beobachtet: Während solche vor allem in der ersten Woche und vor dem ersten Stromeinsatz vorkamen, zeigte kein Pferd einen Abteilwechsel während und nach dem Stromeinsatz. Die Resultate dieser Studie deuten darauf hin, dass der Einsatz von stromführenden Abtrennungen in Führanlagen für Pferde keinen bedeutenden messbaren Stress verursacht.
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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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Quaresmini, C., Forrester, G. S., Spiezio, C., & Vallortigara, G. (2014). Social environment elicits lateralized behaviors in gorillas (Gorilla gorilla gorilla) and chimpanzees (Pan troglodytes). Journal of Comparative Psychology, 128(3), 276–284.
Abstract: The influence of the social environment on lateralized behaviors has now been investigated across a wide variety of animal species. New evidence suggests that the social environment can modulate behavior. Currently, there is a paucity of data relating to how primates navigate their environmental space, and investigations that consider the naturalistic context of the individual are few and fragmented. Moreover, there are competing theories about whether only the right or rather both cerebral hemispheres are involved in the processing of social stimuli, especially in emotion processing. Here we provide the first report of lateralized social behaviors elicited by great apes. We employed a continuous focal animal sampling method to record the spontaneous interactions of a captive zoo-living colony of chimpanzees (Pan troglodytes) and a biological family group of peer-reared western lowland gorillas (Gorilla gorilla gorilla). We specifically focused on which side of the body (i.e., front, rear, left, right) the focal individual preferred to keep conspecifics. Utilizing a newly developed quantitative corpus-coding scheme, analysis revealed both chimpanzees and gorillas demonstrated a significant group-level preference for focal individuals to keep conspecifics positioned to the front of them compared with behind them. More interestingly, both groups also manifested a population-level bias to keep conspecifics on their left side compared with their right side. Our findings suggest a social processing dominance of the right hemisphere for context-specific social environments. Results are discussed in light of the evolutionary adaptive value of social stimulus as a triggering factor for the manifestation of group-level lateralized behaviors. (PsycINFO Database Record (c) 2016 APA, all rights reserved)
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Meriggi, A., Dagradi, V., Dondina, O., Perversi, M., Milanesi, P., Lombardini, M., et al. (2014). Short-term responses of wolf feeding habits to changes of wild and domestic ungulate abundance in Northern Italy. Ethology Ecology & Evolution, 27(4), 389–411.
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Gabor, V., & Gerken, M. (2014). Shetland ponies (Equus caballus) show quantity discrimination in a matching-to-sample design. Anim. Cogn., 17(6), 1233–1243.
Abstract: Numerical competence is one of the aspects of animal cognition with a long history of research interest, but few results are available for the horse. In the present study, we investigated the ability of three Shetland ponies to discriminate between different quantities of geometric symbols presented on a computer screen in a matching-to-sample arrangement. In Experiment 1, the ponies had to relate two similar quantities to another, paired in contrasts (1 vs. 2, 3 vs. 4 and 4 vs. 5) of the same stimulus (dot). Specific pairs of quantities (all differing by one) of up to five different geometrical symbols were displayed in Experiment 2. In each session, both quantities (more and less) were used as sample in such a way that each of the two quantities presented in one test served as positive and as negative stimulus, respectively. The three Shetland ponies were able to discriminate between the given quantities of dots by showing more than 80 % correct responses in two consecutive sessions. Only one of the ponies distinguished different shapes of geometric symbols at a level of 4 versus 5 items. The results show that all ponies were capable of visual quantity discrimination in the present matching-to-sample design, but task solving seemed more difficult when quantities were composed of heterogeneous stimuli. The present results confirm our hypothesis that the ponies based their decision on the matching concept of sameness and were not biased by a spontaneous preference for higher quantities.
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Li, J., & Zhou, X. (2014). Sex, Attractiveness, and Third-Party Punishment in Fairness Consideration. PLoS ONE, 9(4), e94004 EP -.
Abstract: <p>Social evaluation of others is often influenced by the physical attractiveness of the person being judged, leading to either a beauty premium or penalty depending on the circumstances. Here we asked Chinese participants to act as an interest-free third party in a dictator game and to evaluate the fairness level of monetary allocation by attractive and less attractive proposers of the same or opposite sex. We also instructed participants to express their willingness to punish the proposers by using a visual analogue scale. Results confirmed that the reasonableness evaluation was mainly affected by the reasonableness of offers. However, participants' intention to punish the proposers was affected by the level of reasonableness in the asset distribution and by both the sex and attractiveness of the proposers. Overall, male proposers were punished more severely than female proposers. Moreover, the same-sex proposers were punished more severely than opposite-sex proposers when they were physically attractive; this pattern was reversed when the proposers were less physically attractive. These results demonstrate social responses following an individual's unfair asset distribution can be affected by both social norms and the personal characteristics of the individual.</p>
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Méary, D., Li, Z., Li, W., Guo, K., & Pascalis, O. (2014). Seeing two faces together: preference formation in humans and rhesus macaques. Animal Cognition, , 1–13.
Abstract: Humans, great apes and old world monkeys show selective attention to faces depending on conspecificity, familiarity, and social status supporting the view that primates share similar face processing mechanisms. Although many studies have been done on face scanning strategy in monkeys and humans, the mechanisms influencing viewing preference have received little attention. To determine how face categories influence viewing preference in humans and rhesus macaques (Macaca mulatta), we performed two eye-tracking experiments using a visual preference task whereby pairs of faces from different species were presented simultaneously. The results indicated that viewing time was significantly influenced by the pairing of the face categories. Humans showed a strong bias towards an own-race face in an Asian–Caucasian condition. Rhesus macaques directed more attention towards non-human primate faces when they were paired with human faces, regardless of the species. When rhesus faces were paired with faces from Barbary macaques (Macaca sylvanus) or chimpanzees (Pan troglodytes), the novel species’ faces attracted more attention. These results indicate that monkeys’ viewing preferences, as assessed by a visual preference task, are modulated by several factors, species and dominance being the most influential.
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Brinkmann, L., Gerken, M., Hambly, C., Speakman, J. R., & Riek, A. (2014). Saving energy during hard times: Energetic adaptations of Shetland pony mares. J. Exp. Biol., 217, 4320–4327.
Abstract: Recent results suggest that wild Northern herbivores reduce their metabolism during times of low ambient temperatures and food shortage in order to reduce their energetic needs. It is however not known if domesticated animals are also able to reduce their energy expenditure. We exposed ten Shetland pony mares to different environmental conditions (summer and winter) and to two food quantities (60 and 100% of maintenance energy requirement, respectively) during low winter temperatures to examine energetic and behavioural responses. In summer ponies showed a considerably higher field metabolic rate (FMR) (63.4±15.0 MJ d-1) compared to restrictively fed and control animals in winter (24.6±7.8 MJ d-1 and 15.0±1.1 MJ d-1, respectively). During summer conditions locomotor activity, resting heart rates and total water turnover were considerably elevated (P<0.001) compared to winter. Restrictively fed animals (N=5) compensated for the decreased energy supply by reducing their FMR by 26% compared to control animals (N=5). Furthermore, resting heart rate, body mass and body condition score were lower (29.2±2.7 beats min-1; 140±22 kg; 3.0±1.0 points) than in control animals (36.8±41 beats min-1; 165 ±31 kg; 4.4±0.7 points; P<0.05). While the observed behaviour did not change, nocturnal hypothermia was elevated. We conclude that ponies acclimatize to different climatic conditions by changing their metabolic rate, behaviour and some physiological parameters. When exposed to energy challenges, ponies, like wild herbivores, exhibited hypometabolism and nocturnal hypothermia.
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