Abstract: The process of domestication involves adaptation, usually to a captive environment. Domestication is attained by some combination of genetic changes occurring over generations and developmental mechanisms (e.g., physical maturation, learning) triggered by recurring environmental events or management practices in captivity that influence specific biological traits. The transition from free-living to captive status is often accompanied by changes in availability and/or accessibility of shelter, space, food and water, and by changes in predation and the social environment. These changes set the stage for the development of the domestic phenotype. Behavioral development in animals undergoing domestication is characterized by changes in the quantitative rather than qualitative nature of responses. The hypothesized loss of certain behavior patterns under domestication can usually be explained by the heightening of response thresholds. Increases in response frequency accompanying domestication can often be explained by atypical rates of exposure to certain forms of perceptual and locomotor stimulation. Genetic changes influencing the development of the domestic phenotype result from inbreeding, genetic drift, artificial selection, natural selection in captivity, and relaxed selection. Experiential contributions to the domestic phenotype include the presence or absence of key stimuli, changes in intraspecific aggressive interactions and interactions with humans. Man's role as a buffer between the animal and its environment is also believed to have an important effect on the development of the domestic phenotype. The domestication process has frequently reduced the sensitivity of animals to changes in their environment, perhaps the single-most important change accompanying domestication. It has also resulted in modified rates of behavioral and physical development. Interest in breeding animals in captivity for release in nature has flourished in recent decades. The capacity of domestic animals to survive and reproduce in nature may depend on the extent to which the gene pool of the population has been altered during the domestication process and flexibility in behavioral development. “Natural” gene pools should be protected when breeding wild animals in captivity for the purpose of reestablishing free-living natural populations. In some cases, captive-reared animals must be conditioned to live in nature prior to their release.

Abstract: Abstract Concentrated feed diets have been shown to drastically increase the rate of the cribbing, an oral stereotypy in horses, but the specific component causing the rise has not been identified. Furthermore, the mechanism through which feed affects cribbing has not been explored. In the first experiment of this study, we quantified the latency to crib and number of cribs in 15 min after the horses tasted various grain, sugar, and artificial sweetener solutions. Undiluted grain stimulated the most cribs (P < 0.01) compared with all other solutions, and shortest latency to crib, although this was significantly higher only when compared with diluted grain (P = 0.03). In Experiment 2, latency to crib and number of cribs in 15 min after the grain and sugar solutions were administered via nasograstric tube were also evaluated. There were no statistical differences among cribbing responses to grain, fructose, and water administered directly to the stomach although grain stimulated cribbing behavior more quickly than 10% fructose (P = 0.03) and 100% tap water (P = 0.04). These results confirm that highly palatable diets, possibly mediated through the opioid and dopaminergic systems, are one of the most potent inducers of cribbing behavior. The highly palatable taste remains the probable “cribogenic” factor of concentrated diet, although gastric and post-gastric effects cannot be excluded.

Abstract: Welsh pony mares and foals (Equus caballus) were usually found to be within 1 or 5 m of each other during the first week of the foal's life and gradually spent more time at greater distances as the foals became older. There was an overall levelling of the trend during the 9th-15th weeks of life of the foal, followed by a second period of change during weeks 16-24. Through weeks 21-24, mares and foals spent at least half of their time within 5 m of each other. Proximity was primarily due to foal activity except during foal recumbency. During the first 8 weeks of the foal's life, a mare remained close by when it was recumbent, either by grazing in a circle around it or by standing upright beside it. Mares and foals were most likely to be close together when they were resting upright with the other ponies in the herd and most likely to be far apart when the foal was playing. Similarities in patterns of spatial relationship between the foals of a given mare were demonstrated. There was no difference between colts and filies in the development of independence.

Abstract: Processing of serial information was assessed by training six macaques on a five-item list of objects arranged into the four conditional pairs, A-B+, B-C+, C-D+, and D-E+. An analogous list (F through J) was similarly trained. Subsequently, both lists were linked by training on E-F+, a pair that provided adjacent elements from each list. Then, all unique and trained object pairs from both lists were presented as a test. Results indicated that the objects were retained as a single, linearly organized list with choice accuracy directly related to interitem distance between paired objects. A second experiment explored the consequences of incidence of conflicting information on list organization. In both experiments, selections depended on representational processes and supported the view that monkeys and pigeons retain serial lists in qualitatively different ways.

Abstract: The ability of horses to learn and remember new tasks is fundamentally important for their use by humans. Fearfulness may, however, interfere with learning, because stimuli in the environment can overshadow signals from the rider or handler. In addition, prolonged high levels of stress hormones can affect neurons within the hippocampus; a brain region central to learning and memory. In a series of experiments, we aimed to investigate the link between performance in two learning tests, the baseline level of stress hormones, measured as faecal cortisol metabolites (FCM), fearfulness, and social rank. Twenty-five geldings (2 or 3 years old) pastured in one group were included in the study. The learning tests were performed by professional trainers and included a number of predefined stages during which the horses were gradually trained to perform exercises, using either negative (NR) or positive reinforcement (PR). Each of the learning tests lasted 3 days; 7min/horse/day. The NR test was repeated in a novel environment. Performance, measured as final stage in the training programme, and heart rate (HR) were recorded. Faeces were collected on four separate days where the horses had been undisturbed at pasture for 48h. Social rank was determined through observations of social interactions during feeding. The fear test was a novel object test during which behaviour and HR were recorded. Performance in the NR and PR learning tests did not correlate. In the NR test, there was a significant, negative correlation between performance and HR in the novel environment (rS=-0.66, P<0.001, i.e. nervous horses had reduced performance), whereas there was no such correlation in the home environment (both NR and PR). Behavioural reactions in the fear test correlated significantly with performance in the NR test in the novel environment (e.g. object alertness and final stage: rS=-0.43, P=0.04), suggesting that performance under unfamiliar, stressful conditions may be predicted by behavioural responses in a fear test. There was a negative correlation between social rank and baseline stress hormones (rS=-0.43, P=0.04), i.e. high rank corresponded to low FCM concentrations, whereas neither rank nor FCM correlated with fearfulness or learning performance. We conclude that performance under stressful conditions is affected by activation of the sympathetic nervous system during training and related to behavioural responses in a standardised fear test. Learning performance in the home environment, however, appears unrelated to fearfulness, social rank and baseline FCM levels.