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Geisbauer, G., Griebel, U., Schmid, A., & Timney, B. (2004). Brightness discrimination and neutral point. Can. J. Zool, 82(4), 660–670.
Abstract: Abstract: Equine brightness discrimination ability and color discrimination were measured using a two-choice discrimination
task. Two Haflinger horses (Equus caballus L., 1758) were trained to discriminate 30 different shades of grey
varying from low to high relative brightness. Their ability to distinguish shades of grey was poor, with calculated
Weber fractions of 0.42 and 0.45. In addition, a “neutral point” test to determine the dimensionality of color vision
was carried out. Three hues of blue-green were tested versus a range of grey targets with brightnesses similar to those
of the blue-green targets. A neutral point was found at about 480 nm. Thus, we can conclude that horses possess
dichromatic color vision.
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Hogan, J. (2005). Causation: the study of behavioural mechanisms. Animal Biology (formerly Netherlands Journal of Zoology), 55(4), 323–341.
Abstract: This paper describes current work on the causal analysis of behaviour systems. It is noted that while causal work investigating the neural, hormonal, and genetic bases of behaviour is flourishing, work being conducted at a strictly behavioural level of analysis has declined greatly over the past 40 years. Nonetheless, most recent research on animal cognition and applied ethology is still being carried out at a behavioural level of analysis and examples of both types of research are presented: memory mechanisms of food-storing birds and decisions of spider-eating jumping spiders, as well as feather pecking in fowl and animal welfare issues, are all briefly discussed. Finally, I discuss the similarities between neural network modelling and early ethological models of motivation, and then show how a modern version of Lorenz's model of motivation can account for current research findings on dustbathing in chickens and sleep in humans. I conclude that valuable information can still be obtained by research at a behavioural level of analysis.
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Bolhuis, J. (2005). Function and mechanism in neuroecology: looking for clues. Animal Biology (formerly Netherlands Journal of Zoology), 55(4), 457–490.
Abstract: The four questions that Niko Tinbergen identified for behavioural biology ? evolution, function, development and causation ? are all important and should be studied in their own right. Recently, there has been a debate as to whether these four questions should be investigated separately or whether they should be integrated. Integration of the four questions has been attempted in novel research disciplines such as cognitive ecology, evolutionary psychology and neuroecology. Euan Macphail and I have criticised these integrative approaches, suggesting that they are fundamentally flawed as they confound function and mechanism. Investigating the function or evolutionary history of a behaviour or cognitive system is important and entirely legitimate. However, such investigations cannot provide us with answers to questions about the mechanisms underlying behaviour or cognition. At most, functional or evolutionary considerations can provide clues that may be useful for a causal analysis of the underlying mechanisms. However, these clues can be misleading and are often wrong, as is illustrated with examples from song learning and food storing in birds. After summarising the main issues in the neuroecology debate, I discuss some misunderstandings that were apparent in the responses to our critique, as well as some recent relevant data. Recent results do not support the neuroecological approach. Finally, I suggest that the way forward is a cautious and critical use of functional and evolutionary clues in the study of the mechanisms of behaviour.
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King, S. R. B., & Gurnell, J. (2007). Scent-marking behaviour by stallions: an assessment of function in a reintroduced population of Przewalski horses (Equus ferus przewalskii). J Zool, 272(1), 30–36.
Abstract: Abstract Scent marking is a common form of intraspecific communication in mammal species, and using faeces or urine is a cost-effective way of signalling competitive ability and resource holding power. Marking is ritually performed by male equids, and here we assess the function of male scent-marking behaviour in a recently introduced population of Przewalski horses Equus ferus przewalskii in Mongolia. Two forms of scent marking were observed: defecation on stud piles formed from repeated dunging in the same place, and overmarking of faeces and urine of mares. Stud piles were marked with dung by the harem holder and sniffed before and after dung was deposited. They were not found specifically at the periphery of harem ranges but occurred for the most part along routes used by the horses, and were more common in the core parts of harem ranges or where harem ranges overlapped. Thus, rather than being used to defend range boundaries, stud piles were placed predominantly where they would be encountered by male intruders. Mare excreta were covered with urine by the stallion, but were only sniffed before they were marked, not after. These marks appear to advertise to the mare and other, intruding stallions that the harem holder was the mare's consort and that the interloper should not risk trying to steal the mare or sneak a mating. Thus, the two forms of marking by harem holders appear to combine as first and second lines of defence of paternity rights in male intrasexual competition.
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Sigurjonsdottir, H., Thorhallsdottir, A., Hafthorsdottir, H., & Granquist S. (2012). The Behaviour of Stallions in a Semiferal Herd in Iceland: Time Budgets, Home Ranges, and Interactions. International Journal of Zoology, 2012(Article ID 162982).
Abstract: A permanent herd of Icelandic horses with four stallions and their harems was studied for a total of 316 hours in a large pasture (215 ha) in May 2007 in Iceland. Interactions between stallions of different harems and other aspects of the horses' behaviour were studied. One stallion and nine horses were introduced into the pasture prior to the study to examine the reactions of the resident stallions to a newcomer. The stallions spent significantly less time grazing than other horses and were more vigilant. Home ranges overlapped, but harems never mixed. The stallions prevented interactions between members of different harems indirectly by herding. Generally, interactions between resident stallions were nonviolent. However, encounters with the introduced stallion were more aggressive and more frequent than between the other stallions. Here, we show that four harems can share the same enclosure peacefully. The social network seems to keep aggression at a low level both within the harems and the herd as a whole. We encourage horse owners to consider the feasibility of keeping their horses in large groups because of low aggression and because such a strategy gives the young horses good opportunities to develop normally, both physically and socially.
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Leadbeater, E. (2015). What evolves in the evolution of social learning? J Zool, 295(1), 4–11.
Abstract: Social learning is fundamental to social life across the animal kingdom, but we still know little about how natural selection has shaped social learning abilities on a proximate level. Sometimes, complex social learning phenomena can be entirely explained by Pavlovian processes that have little to do with the evolution of sociality. This implies that the ability to learn socially could be an exaptation, not an adaptation, to social life but not that social learning abilities have been left untouched by natural selection. I discuss new empirical evidence for associative learning in social information use, explain how natural selection might facilitate the associative learning process and discuss why such studies are changing the way that we think about social learning.
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