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Koops, M. A., & Abrahams, M. V. (1999). Assessing the Ideal Free Distribution: Do Guppies Use Aggression as Public Information about Patch Quality? Ethology, 105(9), 737–746.
Abstract: Aggression can be costly to foragers, yet some recent research suggests that foragers should use aggression as a cue to patch quality (the attractive aggression hypothesis). If aggression is predictive of patch quality, then the attractive aggression hypothesis predicts that the distribution of foragers should follow the distribution of aggression. If, instead, aggression is repulsive because it is costly, then the distribution of foragers should diverge from the distribution of aggression. We tested the attractive aggression hypothesis using female guppies, Poecilia reticulata, and found that the distribution of foragers followed the distribution of food, but was unaffected by the distribution of aggression. These data do not support the attractive aggression hypothesis, but instead suggest that the distribution of aggression is a consequence of the distribution of foragers, and that aggression is not used as public information about patch quality.
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Goodwin, D. (1999). The importance of ethology in understanding the behaviour of the horse. Equine Vet J Suppl, (28), 15–19.
Abstract: Domestication has provided the horse with food, shelter, veterinary care and protection, allowing individuals an increased chance of survival. However, the restriction of movement, limited breeding opportunities and a requirement to expend energy, for the benefit of another species, conflict with the evolutionary processes which shaped the behaviour of its predecessors. The behaviour of the horse is defined by its niche as a social prey species but many of the traits which ensured the survival of its ancestors are difficult to accommodate in the domestic environment. There has been a long association between horses and man and many features of equine behaviour suggest a predisposition to interspecific cooperation. However, the importance of dominance in human understanding of social systems has tended to overemphasize its importance in the human-horse relationship. The evolving horse-human relationship from predation to companionship, has resulted in serial conflicts of interest for equine and human participants. Only by understanding the nature and origin of these conflicts can ethologists encourage equine management practices which minimise deleterious effects on the behaviour of the horse.
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Odberg, F. O., & Bouissou, M. F. (1999). The development of equestrianism from the baroque period to the present day and its consequences for the welfare of horses. Equine Vet J Suppl, (28), 26–30.
Abstract: Many saddle horses are slaughtered at a young age which could be indicative of a welfare problem. Bad riding is probably an underestimated source of poor welfare. Widespread knowledge of 'academic' riding should be encouraged and should be beneficial to all horses, at all schooling levels, for all purposes. In particular, 18th century principles tend to be forgotten and in this article the authors illustrate some differences to modern dressage. Various suggestions are made in order to improve welfare.
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Clayton, H. M., Lanovaz, J. L., Schamhardt, H. C., & van Wessum, R. (1999). The effects of a rider's mass on ground reaction forces and fetlock kinematics at the trot. Equine Vet J Suppl, 30, 218–221.
Abstract: Ground reaction force (GRF) measurements are often normalised to body mass to facilitate inter-individual comparisons. The objective of this study was to explore the effect of a rider on the GRFs and fetlock joint kinematics of trotting horses. The subjects were 5 dressage-trained horses and 3 experienced dressage riders. Ground reaction force measurements and sagittal view videotapes were recorded as the horses trotted at the same velocity in hand (3.49 +/- 0.52 m/s) and with a rider (3.49 +/- 0.46 m/s). Data were time-normalised to stance duration. Ground reaction force measurements were expressed in absolute terms and normalised to the system mass (horse or horse plus rider). All the horses showed changes in the same direction when comparing the ridden condition with the in-hand condition. There was an increase in the absolute peak vertical GRFs of the fore- and hindlimbs with a rider. However, the mass-normalised peak vertical GRFs were lower for the ridden condition, with the peak occurring later in the forelimbs and earlier in the hindlimbs compared with the inhand condition. Maximal fetlock angle and its time of occurrence were similar for the 2 conditions, but the fore fetlock joint was more extended during the later part of the stance phase in ridden horses. The presence of a rider appeared to affect the GRFs and fetlock joint kinematics differently in the fore- and hindlimbs, and the ridden horse did not seem to be equivalent to a proportionately larger horse. This should be considered when normalising for body mass in studies comparing horses in hand and ridden horses.
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Robinson, I. H. (1999). The human-horse relationship: how much do we know? Equine Vet J Suppl, (28), 42–45.
Abstract: Human relationships or interactions with horses have varied throughout history depending on human needs, but it is horses' ability to carry a human individual that has had perhaps the greatest impact on their relationship with man. Despite our long association with the horse, there have been few studies on human-horse relationships. There is little historical evidence on individual relationships with horses but indications of strong human-horse relationships have been noted in mounted societies, such as North American Plains Indians. Riding a horse has traditionally been associated with power, and was reserved for the ruling elite in many areas. Demographic data suggest that human relationships with horses may have changed in recent times. Although the lack of land and the relatively high cost of horse care may reduce the possibility of ownership for many people, the availability of riding establishments and increases in leisure time mean that riding is no longer restricted to the upper classes. There is a wide range in type and intensity of potential interactions with horses, indicating that human-horse relationships are likely to vary considerably. Some people appear to sacrifice a great deal in order to own a horse. However, the motivation behind these activities and the process by which an individual assesses personal costs of ownership versus their perceived benefits remains to be studied. Future research should focus on characterising the human-horse relationship, and the degree of individual and cultural variation. A greater understanding of horse owner perceptions of 'costs' versus 'benefits' may also increase our understanding of the relationship and the economic importance of horses in society.
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Harman, A. M., Moore, S., Hoskins, R., & Keller, P. (1999). Horse vision and an explanation for the visual behaviour originally explained by the 'ramp retina'. Equine Vet J, 31(5), 384–390.
Abstract: Here we provide confirmation that the 'ramp retina' of the horse, once thought to result in head rotating visual behaviour, does not exist. We found a 9% variation in axial length of the eye between the streak region and the dorsal periphery. However, the difference was in the opposite direction to that proposed for the 'ramp retina'. Furthermore, acuity in the narrow, intense visual streak in the inferior retina is 16.5 cycles per degree compared with 2.7 cycles per degree in the periphery. Therefore, it is improbable that the horse rotates its head to focus onto the peripheral retina. Rather, the horse rotates the nose up high to observe distant objects because binocular overlap is oriented down the nose, with a blind area directly in front of the forehead.
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Goodwin, D. (1999). The importance of ethology in understanding the behaviour of the horse. Equine Veterinary Journal, 31(S28), 15–19.
Abstract: Summary Domestication has provided the horse with food, shelter, veterinary care and protection, allowing individuals an increased chance of survival. However, the restriction of movement, limited breeding opportunities and a requirement to expend energy, for the benefit of another species, conflict with the evolutionary processes which shaped the behaviour of its predecessors. The behaviour of the horse is defined by its niche as a social prey species but many of the traits which ensured the survival of its ancestors are difficult to accommodate in the domestic environment. There has been a long association between horses and man and many features of equine behaviour suggest a predisposition to interspecific cooperation. However, the importance of dominance in human understanding of social systems has tended to overemphasise its importance in the human-horse relationship. The evolving horse-human relationship from predation to companionship, has resulted in serial conflicts of interest for equine and human participants. Only by understanding the nature and origin of these conflicts can ethologists encourage equine management practices which minimise deleterious effects on the behaviour of the horse.
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Mills, D. S., & Nankervis, K. J. (1999).
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Mladenoff, D. J., Sickley, T. A., & Wydeven, A. P. (1999). Predicting gray wolf landscape recolonization: logistic regression models vs. new field data. Ecol Appl, 9.
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Gosling, S. D., & John, O. P. (1999). Personality Dimensions in Nonhuman Animals: A Cross-Species Review. Curr. Dir. Psychol. Sci., 8(3), 69–75.
Abstract: The evolutionary continuity between humans and other animals suggests that some dimensions of personality may be common across a wide range of species. Unfortunately, there is no unified body of research on animal personality; studies are dispersed across multiple disciplines and diverse journals. To review 19 studies of personality factors in 12 nonhuman species, we used the human Five-Factor Model plus Dominance and Activity as a preliminary framework. Extraversion, Neuroticism, and Agreeableness showed the strongest cross-speciesgenerality, followed by Openness; a separate Conscientiousness dimension appeared only in chimpanzees, humans` closest relatives. Cross-species evidence was modest for a separate Dominance dimension but scant for Activity. The comparative approach taken here offers a fresh perspective on human personality and should facilitate hypothesis-driven research on the social and biological bases of personality.
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