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Wallner, B., Palmieri, N., Vogl, C., Rigler, D., Bozlak, E., Druml, T., et al. (2017). Y Chromosome Uncovers the Recent Oriental Origin of Modern Stallions. Current Biology, 27(13), 2029–2035.e5.
Abstract: The Y chromosome directly reflects male genealogies, but the extremely low Y chromosome sequence diversity in horses has prevented the reconstruction of stallion genealogies [1, 2]. Here, we resolve the first Y chromosome genealogy of modern horses by screening 1.46 Mb of the male-specific region of the Y chromosome (MSY) in 52 horses from 21 breeds. Based on highly accurate pedigree data, we estimated the de novo mutation rate of the horse MSY and showed that various modern horse Y chromosome lineages split much later than the domestication of the species. Apart from few private northern European haplotypes, all modern horse breeds clustered together in a roughly 700-year-old haplogroup that was transmitted to Europe by the import of Oriental stallions. The Oriental horse group consisted of two major subclades: the Original Arabian lineage and the Turkoman horse lineage. We show that the English Thoroughbred MSY was derived from the Turkoman lineage and that English Thoroughbred sires are largely responsible for the predominance of this haplotype in modern horses.
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Guidi, A., Lanata, A., Valenza, G., Scilingo, E. P., & Baragli, P. (2017). Validation of smart textile electrodes for electrocardiogram monitoring in free-moving horses. J. Vet. Behav., 17, 19–23.
Abstract: This article focuses on the validation of smart textile electrodes used to acquire electrocardiogram (ECG) signals in horses in a comfortable and robust manner. The performance of smart textile electrodes is compared with standard Ag/AgCl electrodes in terms of the percentage of motion artifacts (MAs, the noise that results from the movement of electrodes against the skin) and signal quality. Seven healthy Standardbred mares were equipped with 2 identical electronic systems for the simultaneous collection of ECGs. One system was equipped with smart textile electrodes, whereas the second was equipped with standard Ag/AgCl electrodes. Each horse was then monitored individually in a stall for 1 hour, without any movement constraints. The ECGs were visually examined by an expert who blindly labeled the ECG segments that had been corrupted by MAs. Finally, the percentage of MAs (MA%) was computed as the number of samples of the corrupted segments over the whole length of the signal. The total MA% was found to be lower for the smart textiles than for the Ag/AgCl electrodes. Consistent results were also obtained by investigating MAs over time. These results suggest that smart textile electrodes are more reliable when recording artifact-free ECGs in horses at rest. Thus, improving the acquisition of important physiological information related to the activity of the autonomic nervous system, such as heart rate variability, could help to provide reliable information on the mood and state of arousal of horses.
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Lanata, A., Guidi, A., Valenza, G., Baragli, P., & Scilingo, E. P. (2017). The Role of Nonlinear Coupling in Human-Horse Interaction: a Preliminary Study. In 2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC).
Abstract: This study focuses on the analysis of humanhorse
dynamic interaction using cardiovascular information
exclusively. Specifically, the Information Theoretic Learning
(ITL) approach has been applied to a Human-Horse Interaction
paradigm, therefore accounting for the nonlinear information
of the heart-heart interplay between humans and horses.
Heartbeat dynamics was gathered from humans and horses
during three experimental conditions: absence of interaction,
visual-olfactory interaction, and brooming. Cross Information
Potential, Cross Correntropy, and Correntropy Coefficient were
computed to quantitatively estimate nonlinear coupling in a
group of eleven subjects and one horse. Results showed a
statistical significant difference on all of the three interaction
phases. Furthermore, a Support Vector Machine classifier
recognized the three conditions with an accuracy of 90:9%.
These preliminary and encouraging results suggest that ITL
analysis provides viable metrics for the quantitative evaluation
of human-horse interaction.
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McLean, A. N., & Christensen, J. W. (2017). The application of learning theory in horse training. Appl. Anim. Behav. Sci., 190, 18–27.
Abstract: The millennia-old practices of horse training markedly predate and thus were isolated from the mid-twentieth century revelation of animal learning processes. From this standpoint, the progress made in the application and understanding of learning theory in horse training is reviewed including a discussion of how learning processes are employed or otherwise under-utilised in training. This review describes the process of habituation and the most commonly applied desensitisation techniques (systematic desensitisation, counter-conditioning, overshadowing, response prevention) and propose two additional techniques (approach conditioning and stimulus blending). The salience of different types of cues, the interaction of operant and classical conditioning and the impact of stress are also discussed. This paper also exposes the inflexibility and occasional inadequacy of the terminology of learning theory when translated from the research laboratory situation to the practical setting in horse training. While learning theory provides a rich toolbox for riders and trainers, the training process is subject to the simultaneous use of multiple learning processes. In addition, learning/behavioural outcomes and trained responses are not just the result of simple stimulus-response based interactions but are further shaped by arousal, affective and attachment states. More research is needed in these areas. For the field of equitation science to progress and to improve clarity and use of learning processes, changes in nomenclature are required. In particular, the use of the terms 'positive' and 'negative' as descriptive labels in both reinforcement and punishment modalities are unacceptably misleading for everyday use. These labels inhibit the understanding and recognition of the learning processes that these terms supposedly represent, yet the learning processes they describe are vital for horse riders, handlers and trainers to understand. We therefore propose that these labels should be re-labelled more appropriately as 'addition' or 'subtraction' reinforcement/punishment. This would enlighten trainers on the correct application of learning theory, and safety and welfare benefits for people and horses would follow. Finally it is also proposed that the term 'conflict theory' be taken up in equitation science to facilitate diagnosis of training-related behaviour disorders and thus enable the emergence of improved training practices. The optimal use of learning theory should be established as a fundamental principle in equestrian education.
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Valenchon, M., Lévy, F., Moussu, C., & Lansade, L. (2017). Stress affects instrumental learning based on positive or negative reinforcement in interaction with personality in domestic horses. Plos One, 12(5), e0170783.
Abstract: The present study investigated how stress affects instrumental learning performance in horses (Equus caballus) depending on the type of reinforcement. Horses were assigned to four groups (N = 15 per group); each group received training with negative or positive reinforcement in the presence or absence of stressors unrelated to the learning task. The instrumental learning task consisted of the horse entering one of two compartments at the appearance of a visual signal given by the experimenter. In the absence of stressors unrelated to the task, learning performance did not differ between negative and positive reinforcements. The presence of stressors unrelated to the task (exposure to novel and sudden stimuli) impaired learning performance. Interestingly, this learning deficit was smaller when the negative reinforcement was used. The negative reinforcement, considered as a stressor related to the task, could have counterbalanced the impact of the extrinsic stressor by focusing attention toward the learning task. In addition, learning performance appears to differ between certain dimensions of personality depending on the presence of stressors and the type of reinforcement. These results suggest that when negative reinforcement is used (i.e. stressor related to the task), the most fearful horses may be the best performers in the absence of stressors but the worst performers when stressors are present. On the contrary, when positive reinforcement is used, the most fearful horses appear to be consistently the worst performers, with and without exposure to stressors unrelated to the learning task. This study is the first to demonstrate in ungulates that stress affects learning performance differentially according to the type of reinforcement and in interaction with personality. It provides fundamental and applied perspectives in the understanding of the relationships between personality and training abilities.
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Liedtke, J., & Schneider, J. M. (2017). Social makes smart: rearing conditions affect learning and social behaviour in jumping spiders. Anim. Cogn., 20(6), 1093–1106.
Abstract: There is a long-standing debate as to whether social or physical environmental aspects drive the evolution and development of cognitive abilities. Surprisingly few studies make use of developmental plasticity to compare the effects of these two domains during development on behaviour later in life. Here, we present rearing effects on the development of learning abilities and social behaviour in the jumping spider Marpissa muscosa. These spiders are ideally suited for this purpose because they possess the ability to learn and can be reared in groups but also in isolation without added stress. This is a critical but rarely met requirement for experimentally varying the social environment to test its impact on cognition. We split broods of spiders and reared them either in a physically or in a socially enriched environment. A third group kept under completely deprived conditions served as a 'no-enrichment' control. We tested the spiders' learning abilities by using a modified T-maze. Social behaviour was investigated by confronting spiders with their own mirror image. Results show that spiders reared in groups outperform their conspecifics from the control, i.e. 'no-enrichment', group in both tasks. Physical enrichment did not lead to such an increased performance. We therefore tentatively suggest that growing up in contact with conspecifics induces the development of cognitive abilities in this species.
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Schuetz, A., Farmer, K., & Krueger, K. (2017). Social learning across species: horses (Equus caballus) learn from humans by observation. Anim. Cogn., 20(3), 567–573.
Abstract: This study examines whether horses can learn by observing humans, given that they identify individual humans and orientate on the focus of human attention. We tested 24 horses aged between 3 and 12. Twelve horses were tested on whether they would learn to open a feeding apparatus by observing a familiar person. The other 12 were controls and received exactly the same experimental procedure, but without a demonstration of how to operate the apparatus. More horses from the group with demonstration (8/12) reached the learning criterion of opening the feeder twenty times consecutively than horses from the control group (2/12), and younger horses seemed to reach the criterion more quickly. Horses not reaching the learning criteria approached the human experimenters more often than those that did. The results demonstrate that horses learn socially across species, in this case from humans.
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KOIZUMI, R., MITANI, T., UEDA, K., & KONDO, S. (2017). Skill reading of human social cues by horses (Equus caballus) reared under year-round grazing conditions. Animal Behaviour and Management, 53(2), 69–78.
Abstract: Animals use communicative signals, such as gesture or gaze, to communicate to someone the intention or expression of the sender, which is called social cue. In the previous studies, it was suggested the skill of reading human social cue in domestic animals are influenced to the domestication, the experience contacting with human and training to obey human. In this present study, we tested the skill for horses (Equus caballus) kept in year-round grazing conditions using 33 horses differed from breed and the degree of the experience with human by object-choice task subjects choosing either of bait boxes located at the end of experimenter. As results, non-socialized horses hardly responded to human social cues. Habituated horses that were both of trained and untrained responded to human social cues, but their accuracy rates were not more than 50% except for two trained subjects. For the skill of reading human social cues, there was high individual variation in responding to human social cues in horses kept in year-round grazing conditions. The individual characteristics influenced to it more than domestication, the experience with human, and training to obey human.
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Passilongo, D., Marchetto, M., & Apollonio, M. (2017). Singing in a wolf chorus: structure and complexity of a multicomponent acoustic behaviour. Hysterix, 28(2), 180–185.
Abstract: Wolf choruses ( Canis lupus ) are complex, multicomponent signals, composed by a series of different vocalizations emitted by a pack. Although howls, the main component, have been highly studied, poor attention has been drawn upon the other vocalizations of the chorus. In this study, we investigate the structure of the chorus by means of the analysis and the quantification of the different components, taking advantage both of the digital sound recording and analysis, and of the modern statistical methodologies. We provide for the first time a detailed, objective description of the types of call emitted during the wolf howlings, combining spectrographic examinations, spectral analyses and automated classifications, with the aim to identify different types of call. Our results show that wolf choruses have a rich, complex structure, that reveals six other types of call, to be added to those howls already described in literature. Wolf choruses are typically composed by other three different types of calls: the bark, i.e. relatively long calls characterized by low frequencies and the presence of harsh components (deterministic chaos); the whimper, characterized by a harmonic structure and a very short duration; and the growl, a call with a noisy structure, low frequencies but relative long duration. Although further investigations are necessary to understand the meaning of the different calls, this research provides a basis for those studies that aim to compare wolves and other canids vocal behaviour.
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Knolle, F., Goncalves, R. P., & Morton, A. J. (2017). Sheep recognize familiar and unfamiliar human faces from two-dimensional images. Royal Society Open Science, 4(11).
Abstract: One of the most important human social skills is the ability to recognize faces. Humans recognize familiar faces easily, and can learn to identify unfamiliar faces from repeatedly presented images. Sheep are social animals that can recognize other sheep as well as familiar humans. Little is known, however, about their holistic face-processing abilities. In this study, we trained eight sheep (Ovis aries) to recognize the faces of four celebrities from photographic portraits displayed on computer screens. After training, the sheep chose the 'learned-familiar' faces rather than the unfamiliar faces significantly above chance. We then tested whether the sheep could recognize the four celebrity faces if they were presented in different perspectives. This ability has previously been shown only in humans. Sheep successfully recognized the four celebrity faces from tilted images. Interestingly, there was a drop in performance with the tilted images (from 79.22 ± 7.5% to 66.5 ± 4.1%) of a magnitude similar to that seen when humans perform this task. Finally, we asked whether sheep could recognize a very familiar handler from photographs. Sheep identified the handler in 71.8 ± 2.3% of the trials without pretraining. Together these data show that sheep have advanced face-recognition abilities, comparable with those of humans and non-human primates.
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