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Smith, A. V., Proops, L., Grounds, K., Wathan, J., & McComb, K. (2016). Functionally relevant responses to human facial expressions of emotion in the domestic horse (Equus caballus). Biol. Lett., 12(2).
Abstract: Whether non-human animals can recognize human signals, including emotions, has both scientific and applied importance, and is particularly relevant for domesticated species. This study presents the first evidence of horses' abilities to spontaneously discriminate between positive (happy) and negative (angry) human facial expressions in photographs. Our results showed that the angry faces induced responses indicative of a functional understanding of the stimuli: horses displayed a left-gaze bias (a lateralization generally associated with stimuli perceived as negative) and a quicker increase in heart rate (HR) towards these photographs. Such lateralized responses towards human emotion have previously only been documented in dogs, and effects of facial expressions on HR have not been shown in any heterospecific studies. Alongside the insights that these findings provide into interspecific communication, they raise interesting questions about the generality and adaptiveness of emotional expression and perception across species.
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Cinková, I., & Policht, R. (2016). Sex and species recognition by wild male southern white rhinoceros using contact pant calls. Anim. Cogn., 19(2), 375–386.
Abstract: Recognition of information from acoustic signals is crucial in many animals, and individuals are under selection pressure to discriminate between the signals of conspecifics and heterospecifics or males and females. Here, we first report that rhinos use information encoded in their calls to assess conspecifics and individuals of closely related species. The southern (Ceratotherium simum) and critically endangered northern (C. cottoni) white rhinos are the most social out of all the rhinoceros species and use a contact call pant. We found that southern white rhino pant calls provide reliable information about the caller’s sex, age class and social situation. Playback experiments on wild territorial southern white rhinoceros males revealed that they responded more strongly to the pant calls of conspecific females compared to the calls of other territorial males. This suggests that pant calls are more important form of communication between males and females than between territorial males. Territorial southern males also discriminated between female and territorial male calls of northern species and reacted more intensively to the calls of northern than southern males. This might be caused by a novelty effect since both species naturally live in allopatry. We conclude that white rhinos can directly benefit from assessing individuals at long distances using vocal cues especially because their eyesight is poor. Pant calls thus likely play a significant role in their social relationships and spatial organization. In addition, better understanding of vocal communication in white rhinos might be helpful in conservation management particularly because of their low reproduction in captivity.
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Chapron, G., & Treves, A. (2016). Blood does not buy goodwill: allowing culling increases poaching of a large carnivore. Proc. R. Soc. Lond. B, 283(1830).
Abstract: Quantifying environmental crime and the effectiveness of policy interventions is difficult because perpetrators typically conceal evidence. To prevent illegal uses of natural resources, such as poaching endangered species, governments have advocated granting policy flexibility to local authorities by liberalizing culling or hunting of large carnivores. We present the first quantitative evaluation of the hypothesis that liberalizing culling will reduce poaching and improve population status of an endangered carnivore. We show that allowing wolf (Canis lupus) culling was substantially more likely to increase poaching than reduce it. Replicated, quasi-experimental changes in wolf policies in Wisconsin and Michigan, USA, revealed that a repeated policy signal to allow state culling triggered repeated slowdowns in wolf population growth, irrespective of the policy implementation measured as the number of wolves killed. The most likely explanation for these slowdowns was poaching and alternative explanations found no support. When the government kills a protected species, the perceived value of each individual of that species may decline; so liberalizing wolf culling may have sent a negative message about the value of wolves or acceptability of poaching. Our results suggest that granting management flexibility for endangered species to address illegal behaviour may instead promote such behaviour.
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Tebbich Sabine, Griffin Andrea S., Peschl Markus F., & Sterelny Kim. (2016). From mechanisms to function: an integrated framework of animal innovation. Philos Trans R Soc Lond B Biol Sci, 371(1690), 20150195.
Abstract: Animal innovations range from the discovery of novel food types to the invention of completely novel behaviours. Innovations can give access to new opportunities, and thus enable innovating agents to invade and create novel niches. This in turn can pave the way for morphological adaptation and adaptive radiation. The mechanisms that make innovations possible are probably as diverse as the innovations themselves. So too are their evolutionary consequences. Perhaps because of this diversity, we lack a unifying framework that links mechanism to function. We propose a framework for animal innovation that describes the interactions between mechanism, fitness benefit and evolutionary significance, and which suggests an expanded range of experimental approaches. In doing so, we split innovation into factors (components and phases) that can be manipulated systematically, and which can be investigated both experimentally and with correlational studies. We apply this framework to a selection of cases, showing how it helps us ask more precise questions and design more revealing experiments.
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Sommer, V., Lowe, A., & Dietrich, T. (2016). Not eating like a pig: European wild boar wash their food. Anim. Cogn., 19(1), 245–249.
Abstract: Carrying food to water and either dunking or manipulating it before consumption has been observed in various taxa including birds, racoons and primates. Some animals seem to be simply moistening their food. However, true washing aims to remove unpleasant surface substrates such as grit and sand and requires a distinction between items that do and do not need cleaning as well as deliberate transportation of food to a water source. We provide the first evidence for food washing in suids, based on an incidental observation with follow-up experiments on European wild boar (Sus scrofa) kept at Basel Zoo, Switzerland. Here, all adult pigs and some juveniles of a newly formed group carried apple halves soiled with sand to the edge of a creek running through their enclosure where they put the fruits in the water and pushed them to and fro with their snouts before eating. Clean apple halves were never washed. This indicates that pigs can discriminate between soiled and unsoiled foods and that they are able to delay gratification for long enough to transport and wash the items. However, we were unable to ascertain to which degree individual and/or social learning brought this behaviour about.
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Mori, E., Benatti, L., Lovari, S., & Ferretti, F. (2016). What does the wild boar mean to the wolf? European Journal of Wildlife Research, 63(1), 9.
Abstract: Generalist predators are expected to shape their diets according to the local availability of prey species. In turn, the extent of consumption of a prey would be influenced by the number of alternative prey species. We have tested this prediction by considering the wild boar and the grey wolf: two widespread species whose distribution ranges overlap largely in Southern Europe, e.g. in Italy. We have reviewed 16 studies from a total of 21 study areas, to assess whether the absolute frequency of occurrence of wild boar in the wolf diet was influenced by (i) occurrence of the other ungulate species in diet and (ii) the number of available ungulate species. Wild boar turned out to be the main prey of the wolf (49% occurrence, on average), followed by roe deer (24%) and livestock (18%). Occurrence of wild boar in the wolf diet decreased with increasing usage of roe deer, livestock, and to a lower extent, chamois and red deer. The number of prey species did not influence the occurrence of wild boar in the wolf diet. The wild boar is a gregarious, noisy and often locally abundant ungulate, thus easily detectable, to a predator. In turn, the extent of predation on this ungulate may not be influenced so much by the availability of other potential prey. Heavy artificial reductions of wild boar numbers, e.g. through numerical control, may concentrate predation by wolves on alternative prey (e.g. roe deer) and/or livestock, thus increasing conflicts with human activities.
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Gleerup, K. B., & Lindegaard, C. (2016). Recognition and quantification of pain in horses: A tutorial review. Equine Vet Educ, 28(1), 47–57.
Abstract: Summary Pain management is dependent on the quality of the pain evaluation. Ideally, pain evaluation is objective, pain-specific and easily incorporated into a busy equine clinic. This paper reviews the existing knowledge base regarding the identification and quantification of pain in horses. Behavioural indicators of pain in horses in the context of normal equine behaviour, as well as various physiological parameters potentially useful for pain evaluation, are discussed. Areas where knowledge is sparse are identified and a new equine pain scale based on results from all reviewed papers is proposed. Finally, the most important considerations in relation to the implementation of a pain scale in a hospital setting are discussed.
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Horowitz, A., & Hecht, J. (2016). Examining dog–human play: the characteristics, affect, and vocalizations of a unique interspecific interaction. Anim. Cogn., , 1–10.
Abstract: Despite the growing interest in research on the interaction between humans and dogs, only a very few research projects focus on the routines between dogs and their owners. In this study, we investigated one such routine: dog–human play. Dyadic interspecific play is known to be a common interaction between owner and charge, but the details of what counts as play have not been thoroughly researched. Similarly, though people represent that “play” is pleasurable, no study has yet undertaken to determine whether different forms of play are associated with different affective states. Thus, we aimed to generate an inventory of the forms of dyadic play, the vocalizations within play, and to investigate the relationship of affect to elements of play. Via a global citizen science project, we solicited videotapes of dog–human play sessions from dog owners. We coded 187 play bouts via frame-by-frame video playback. We then assessed the relationship between various intra-bout variables and owner affect (positive or neutral) during play (dog affect was overwhelmingly positive). Amount of physical contact (“touch”), level of activity of owner (“movement”), and physical closeness of dog–owner dyad (“proximity”) were highly correlated with positive affect. Owner vocalizations were found to contain different elements in positive- and neutral-affect play. One novel category of play, “tease”, was found. We conclude that not all play is created equal: the experience of play to the owner participant is strongly related to a few identifiable characteristics of the interaction.
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Marr, I., Bauer, T., Farmer, K., & Krueger, K. (2016). Gibt die sensorische Lateralität im Objekttest Aufschluss über das Interieur, den aktuellen Gemütszustand, oder den Trainingszustand der Pferde? In 33. FFP-Jahrestagung.
Abstract: Vor dem obersten Ziel der klassischen Ausbildungsskala für Pferde, die Versammlung, steht das Geraderichten. Ein jedes Pferd ist jedoch von Geburt an asymmetrisch, also schief. Hinter dieser Schiefe verbirgt sich nicht nur die natürliche Schiefe (asymmetrische muskuläre Entwicklung der beiden Körperhälften), die von Geburt an zu beobachten ist, sondern auch die sensorische und motorische Lateralität, also dem ungleichmäßigen Gebrauch der rechten oder linken Sinnesorgane sowie Gliedmaßen, der sich mit der Reifung des Gehirns entwickelt. Alle drei müssen als eigenständige Faktoren, die sich gegenseitig beeinflussen, gesehen werden (Krüger 2014). Um den Weg des Geraderichtens zu erleichtern, sollte in der Ausbildung eines Pferdes nicht nur an der natürlichen Schiefe gearbeitet werden, sondern auch die sensorische und motorische Lateralität beachtet werden um den Prozess des Geraderichtens für das Pferd zu erleichtern. Die sensorische und motorische Lateralität resultiert aus der Aufgabenteilung/Spezialisierung beider Gehirnhälften (Hemisphären) (Rogers 2010). Die rechte Hemisphäre ist dabei für die Verarbeitung von Emotionen (z.B. Angst, Aggression, Freude, Zufriedenheit) sowie für lebenserhaltende Spontanreaktionen zuständig. Die linke Hemisphäre ist für die rationale Verarbeitung von Informationen essentiell (Adolphs et al. 1996, Rogers 2010, Austin und Rogers 2012, De Boyer Des Roches et al. 2008, Demaree et al. 2005, Austin und Rogers 2014). Rückschlüsse auf die Informationsverarbeitung lassen sich über die Beobachtung der verwendeten Sinnesorgane (Ohren und Augen) ziehen, die kontralateral mit den Großhirnhemisphären verbunden sind (Brooks et al. 1999). Es wird vermutet, dass Stress zu einer verstärkten Informationsverarbeitung durch die rechte Großhirnhemisphäre führt (Rogers 2010, Schultheiss et al. 2009). Diese konnte auch in ersten Untersuchungen am Pferd bestätigt werden (unveröffentlichte Daten). Forscher, die den einseitigen Gebrauch von rechten und linken Gliedmaßen (motorische Lateralität) bei Menschen und Tieren untersuchten, zeigten weiterhin Zusammenhänge zur Emotionalität und Reaktivität (McGreevy und Thomson 2006, Rogers 2009, Austin und Rogers 2012, Deesing und Grandin 2014). Die Tendenz zum einseitigen Gebrauch der Gliedmaßen gibt Hinweise auf den „Cognitive Bias“ (= individuelle, kognitive Verzerrung der Wahrnehmung und Verarbeitung von Informationen ins Positive oder Negative) und steht im Zusammenhang mit der persönlichen Neigung auf Stressfaktoren zu reagieren (zusammengefasst von Rogers 2010). Die sensorische Lateralität ändert sich jedoch schneller und situationsgebundener als die motorische Lateralität. Sie wird mittels Objekttests bestimmt, die ebenfalls verwendet werden können um die Reaktivität und Emotionalität zu untersuchen. Für eine objektivere Beurteilung des Interieurs eines Pferdes ist daher zu überlegen, ob die sensorische Lateralität als objektiver Parameter integriert werden kann, welchen Einflüssen diese unterliegt und mit welchen Persönlichkeitsmerkmalen sie korreliert. Wie in der Studie von Farmer et al. (2010) dargestellt werden konnte, zeigten bilateral trainierte Pferde eine weniger stark ausgeprägte Präferenz für die linken Sinnesorgane als traditionell trainierte Pferde in Tests mit Personen (ohne Interaktion). Es stellt sich daher die Frage, ob diese Beobachtung ein Resultat von langjährigem Training ist oder ob es sich bereits nach wenigen Wochen Training einstellt sowie ob solche Entwicklungen auch bei Objekten beobachtet werden können.
Für die erste Untersuchung ergaben sich daher in dieser Studie folgende Fragstellungen: Sind die Ergebnisse eines Objekttests mit Evaluierung der sensorischen Lateralität hinsichtlich der Lateralität wiederholbar? Denn, sollte es möglich sein mittels der sensorische Lateralität auf bestimmte
Persönlichkeitsmerkmale rückschließen zu können, so muss diese genauso stabil und reproduzierbar sein, wie die betreffenden Persönlichkeitsmerkmale. Unterscheiden sich Pferde hinsichtlich ihrer Lateralität in Objekttests, die bereits intensiv gleichmäßig beidseitig trainiert wurden, von Pferden, bei denen weniger Augenmerk auf gleichmäßiges beidseitiges Training gelegt wurde? Kann die Lateralität in Objekttests mit einer definierten gleichmäßigen beidseitigen Trainingsmethode beeinflusst werden? In welche Richtung verschiebt sich gegebenenfalls die Lateralität? Beeinflusst das Alter gegebenenfalls das Ausmaß von Veränderungen, da sich die sensorische Lateralität mit der Reifung des Gehirns entwickelt?
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Leliveld, L. M. C., Düpjan, S., Tuchscherer, A., & Puppe, B. (2016). Behavioural and physiological measures indicate subtle variations in the emotional valence of young pigs. Physiol. Behav., 157, 116–124.
Abstract: Abstract In the study of animal emotions, emotional valence has been found to be difficult to measure. Many studies of farm animals' emotions have therefore focussed on the identification of indicators of strong, mainly negative, emotions. However, subtle variations in emotional valence, such as those caused by rather moderate differences in husbandry conditions, may also affect animals' mood and welfare when such variations occur consistently. In this study, we investigated whether repeated moderate aversive or rewarding events could lead to measurable differences in emotional valence in young, weaned pigs. We conditioned 105 female pigs in a test arena to either a repeated startling procedure (sudden noises or appearances of objects) or a repeated rewarding procedure (applesauce, toy and straw) over 11 sessions. Control pigs were also regularly exposed to the same test arena but without conditioning. Before and after conditioning, we measured heart rate and its variability as well as the behavioural reactions of the subjects in the test arena, with a special focus on detailed acoustic analyses of their vocalisations. The behavioural and heart rate measures were analysed as changes compared to the baseline values before conditioning. A limited number of the putative indicators of emotional valence were affected by the conditioning. We found that the negatively conditioned pigs showed changes that were significantly different from those in control pigs, namely a decrease in locomotion and an increase in standing. The positively conditioned pigs, however, showed a stronger increase in heart rate and a smaller decrease in SDNN (a heart rate variability parameter indicating changes in autonomic regulation) compared to the controls. Compared to the negatively conditioned pigs, the positively conditioned pigs produced fewer vocalisations overall as well as fewer low-frequency grunts but more high-frequency grunts. The low-frequency grunts of the negatively conditioned pigs also showed lower frequency parameters (bandwidth, maximum frequency, 25% and 50% quartiles) compared to those of the positively conditioned pigs. In any of the statistically significant results, the conditioning accounted for 1.5–11.9% of variability in the outcome variable. Hence, we conclude that repeated moderate aversive and rewarding events have weak but measurable effects on some aspects of behaviour and physiology in young pigs, possibly indicating changes in emotional valence, which could ultimately affect their welfare. The combination of ethophysiological indicators, i.e., the concurrent examination of heart rate measures, behavioural responses and especially vocalisation patterns, as used in the current study, might be a useful way of examining subtle effects on emotional valence in further studies.
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