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Imura, T., & Tomonaga, M. (2003). Perception of depth from shading in infant chimpanzees ( Pan troglodytes). Anim. Cogn., 6(4), 253–258.
Abstract: We investigated the ability to perceive depth from shading, one of the pictorial depth cues, in three chimpanzee infants aged 4-10 months old, using a preferential reaching task commonly used to study pictorial depth perception in human infants. The chimpanzee infants reached significantly more to three-dimensional toys than to pictures thereof and more to the three-dimensional convex than to the concave. Furthermore, two of the three infants reached significantly more to the photographic convex than to the photographic concave. These infants also looked longer at the photographic convex than the concave. Our results suggest that chimpanzees perceive, at least as early as the latter half of the first year of life, pictorial depth defined by shading information. Photographic convexes contain richer information about pictorial depth (e.g., attached shadow, cast shadow, highlighted area, and global difference in brightness) than simple computer-graphic graded patterns. These cues together might facilitate the infants' perception of depth from shading.
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Borsari, A., & Ottoni, E. B. (2005). Preliminary observations of tool use in captive hyacinth macaws (Anodorhynchus hyacinthinus). Anim. Cogn., 8(1), 48–52.
Abstract: Many animals use tools (detached objects applied to another object to produce an alteration in shape, position, or structure) in foraging, for instance, to access encapsulated food. Descriptions of tool use by hyacinth macaws (Anodorhynchus hyacinthinus) are scarce and brief. In order to describe one case of such behavior, six captive birds were observed while feeding. Differences in nut manipulation and opening proficiency between adults and juveniles were recorded. The tools may be serving as a wedge, preventing the nut from slipping and/or rotating, reducing the impact of opening, or providing mechanical aid in its positioning and/or use of force. Data suggest that birds of this species have an innate tendency to use objects (tools) as aids during nut manipulation and opening.
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Kendal, R. L., Coe, R. L., & Laland, K. N. (2005). Age differences in neophilia, exploration, and innovation in family groups of callitrichid monkeys. Am. J. Primatol., 66(2), 167–188.
Abstract: The prevailing assumption in the primate literature is that young or juvenile primates are more innovative than adult individuals. This innovative tendency among the young is frequently thought to be a consequence, or side effect, of their increased rates of exploration and play. Conversely, Reader and Laland's [International Journal of Primatology 22:787-806, 2001] review of the primate innovation literature noted a greater reported incidence of innovation in adults than nonadults, which they interpreted as (in part) a reflection of the greater experience and competence of older individuals. Within callitrichids there is contradictory evidence for age differences in response to novel objects, foods, and foraging tasks. By presenting novel extractive foraging tasks to family groups of callitrichid monkeys in zoos, we examined, in a large sample, whether there are positive or negative relationships of age with neophilia, exploration, and innovation, and whether play or experience most facilitates innovation. The results indicate that exploration and innovation (but not neophilia) are positively correlated with age, perhaps reflecting adults' greater manipulative competence. To the extent that there was evidence for play in younger individuals, it did not appear to contribute to innovation. The implications of these findings for the fields of innovation and conservation through reintroduction are considered.
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Cambefort, J. P. (1981). A comparative study of culturally transmitted patterns of feeding habits in the chacma baboon Papio ursinus and the vervet monkey Cercopithecus aethiops. Folia Primatol (Basel), 36(3-4), 243–263.
Abstract: Japanese workers have studied social acquisition patterns of new feeding habits in Macaca fuscata which they have termed precultural. The present study investigates the same phenomenon in the chacma baboon and the vervet monkey in their natural habitat. The questions addressed are: (1) How a new feeding habit enters a troop and by which age and sex category, also how it is propagated? (2) When individuals are permitted with a choice between palatable and unpalatable food, can they learn by demonstration only or do they have to pass through a direct learning process? (3) Can the results from the above questions be explained by social parameters such as the social structure of the individual species? It was found that juvenile baboons discover new food and that after the discovery propagation is instantaneous. In vervets discovery is random among the age classes and propagation is slow and takes place through certain 'pivot' individuals. Both species fail to learn about palatability by demonstration but have to go through a direct learning process. This contrasts strongly with the forest baboon Mandrillus sphinx that have been shown to learn by demonstration. Socially, baboon juveniles stay closer to each other than the adults who force them to live at the periphery of the troop. Vervets again forage without precise sub-group formation. The link between social and cultural propagation and social structure is discussed on the basis of these findings.
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Hinde, R. A. (1969). Analyzing the roles of the partners in a behavioral interaction--mother-infant relations in rhesus macaques. Ann N Y Acad Sci, 159(3), 651–667.
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Feist, J. D., & McCullough, D. R. (1975). Reproduction in feral horses. J Reprod Fertil Suppl, (23), 13–18.
Abstract: A behavioural study of feral horses was conducted on the Pryor Mountain Wild Horse Range in the western United States. All 270 horses on the Range were identified individually. The sex ratio was nearly balanced. Foal to adult female ratio was 43-2:100. Morality was concentrated among foals and old horses. Horses were organized as forty-four harem groups each with a dominant stallion, one to two immature stallions, one to three immature mares, one to three adult mares and their yearling and foal offspring, and 23 bachelor groups of one to eight stallions. Harem groups were quite stable year-round because of dominance and leadership by the stallions and group fidelity by mares and their offsring. Most changes occurred during the breeding season and involved immature females. Defeat of dominant stallions was infrequent. Immature males were tolerated because of their submissive behaviour. Bachelor stallion groups were inherently unstable. Mares came into heat after foaling in May/June, and were mated by harem stallions only.
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Harkins, J. D., Kamerling, S. G., & Church, G. (1992). Effect of competition on performance of thoroughbred racehorses. J Appl Physiol, 72(3), 836–841.
Abstract: The effect of competition and the influence of age and sex on performance were examined in a study of 18 Thoroughbred racehorses. The horses performed two solo and two competitive runs at 1,200 and 1,600 m for a total of eight runs. No group ran faster during competition, which may have been a reflection of the quality of horses used for this study and their susceptibility to stress-induced impairment of performance. Males showed no significant difference between competitive and solo run times, whereas females were consistently slower during competition. Males ran significantly faster than females in all runs. There was no difference in run times due to age, which may have been due to the high mean age (5.9 yr) of the group. The slower competitive run times may have occurred because of an earlier onset of fatigue when compared with solo runs. Plasma lactate was significantly greater for the 1,200-m competitive than for the solo runs.
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Williams, J. L., Friend, T. H., Collins, M. N., Toscano, M. J., Sisto-Burt, A., & Nevill, C. H. (2003). Effects of imprint training procedure at birth on the reactions of foals at age six months. Equine Vet J, 35(2), 127–132.
Abstract: REASONS FOR PERFORMING STUDY: While imprint training procedures have been promoted in popular magazines, they have received limited scientific investigation. OBJECTIVES: To determine the effects of a neonatal imprint training procedure on 6-month-old foals and to determine if any one session had a greater effect than others. METHODS: Foals (n = 131) were divided into the following treatments: no imprint training, imprint training at birth, 12, 24 and 48 h after birth or imprint training only at birth, 12, 24, 48, or 72 h after birth. Foals then received minimal human handling until they were tested at 6 months. RESULTS: During training, time to complete exposure to the stimulus was significant for only 2 of 6 stimuli. Percentage change in baseline heart rate was significant for only 2 of 10 stimuli. These 4 effects were randomly spread across treatments. CONCLUSIONS: Neither the number of imprint training sessions (0, 1, or 4) nor the timing of imprint training sessions (none, birth, 12, 24, 48, or 72 h after birth) influenced the foal's behaviour at 6 months of age. POTENTIAL CLINICAL RELEVANCE: In this study, imprint training did not result in better behaved, less reactive foals.
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Pinchbeck, G. L., Clegg, P. D., Proudman, C. J., Morgan, K. L., & French, N. P. (2004). A prospective cohort study to investigate risk factors for horse falls in UK hurdle and steeplechase racing. Equine Vet J, 36(7), 595–601.
Abstract: REASONS FOR PERFORMING STUDY: Equine fatalities during racing continue to be a major welfare concern and falls at fences are responsible for a proportion of all equine fatalities recorded on racecourses. OBJECTIVES: To identify and quantify risk factors for horse falls in National Hunt (NH) racing and to report the frequency of falling and falling-associated fatalities. METHODS: A prospective cohort study was conducted on 2879 horse starts in hurdle and steeplechase races on 6 UK racecourses. Any horse that suffered a fall at a steeplechase or hurdle fence during the race was defined as a case. Data were obtained by interview and observations in the parade ring and from commercial databases. Multivariable logistic regression models, allowing for clustering at the level of the track, were used to identify the relationship between variables and the risk of falling. RESULTS: There were 124 falling cases (32 in hurdling and 92 in steeplechasing) identified. The injury risk of fallers was 8.9% and fatality risk 6.5%. Duration of journey to the racecourse, behaviour in the parade ring and weather at the time of the race were associated with falling in both hurdle and steeplechase racing. Age, amount of rainfall and going were also associated with falling in steeplechase racing. CONCLUSIONS: Falls at fences are significant contributors to equine fatalities during NH racing. Potentially modifiable risk factors identified were the condition of track surfaces and journey time to the racecourse. POTENTIAL RELEVANCE: It is hoped that information from this study may be used in future interventions to improve horse and jockey safety in racing. The study has also identified areas requiring further research, such as equine behaviour and its effect on racing performance, and the effect of light conditions on jumping ability.
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Jonsson, H., & Egenvall, A. (2006). Prevalence of gastric ulceration in Swedish Standardbreds in race training. Equine Vet J, 38(3), 209–213.
Abstract: REASONS FOR PERFORMING STUDY: There is little information about the prevalence of gastric ulcers in Standardbred trotters and potential correlations between ulcers and various traits, e.g. age, sex, performance, temperament and feeding regimens, need further elucidation. OBJECTIVES: The prevalence of ulcers in the gastric squamous mucosa of Swedish Standardbreds was estimated and the associations between ulcer score and age, sex, performance, temperament and feeding regimens were determined. METHODS: Eighty Swedish Standardbreds in active race training, trained by 9 different trainers, underwent gastroscopy. Information on age, gender, status of training, performance over the last 4 months compared with the trainer's expectations before that period, behaviour, eating habits, feed type, bedding type, time spent outdoors per day and medical treatment during the last month was collected. Gastroscopy was performed and lesions in the squamous gastric mucosa were scored from 0 to 4 (0 = no lesions; 4 = > 5 lesions with haemorrhage, > 10 lesions with no haemorrhage, or a large area of diffuse loss of surface epithelium). RESULTS: Twenty-four (30%) of the horses had no lesions in the squamous mucosa, 22 (27.5%) had a score of 1; 21 (26.2%) score 2; 9 (11.2%) score 3; and 4 (5%) score 4. Horses that were in preparatory training and those that had raced during the last month were significantly more affected than horses that were fit for racing but had not raced during the last month, using a logistic regression model with trainer incorporated as a random effect. CONCLUSIONS: The study confirmed a high prevalence of ulcers in the gastric squamous mucosa of Standardbreds in race training. Of the studied parameters only status of training showed a significant association with gastric ulcers of the squamous mucosa. POTENTIAL RELEVANCE: Gastric ulceration is a common disease and diagnosis should be made by endoscopic examination of the gastric mucosa, since parameters such as age, gender, performance, behaviour, eating habits provide only weak clues as to which horses might be affected. Further studies are needed to determine the aetiology of the syndrome and to find ways to reduce, if possible, the frequency of gastric ulcers.
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