Abstract: Zebrafish (Danio rerio) provide an excellent model for assessment of molecular processes of neurodevelopment. To determine the functional importance of molecular events during neurodevelopment, we have developed methods for assessing learning in zebrafish in a three-chambered fish tank. In the first study, simple escape response was assessed. Zebrafish tested with a moving net learned to escape to another chamber more rapidly over the six sessions of training than the fish with the still net which did not learn. Upon reversal of the contingencies, the fish switched to the inactive net rapidly learned to suppress the escape response and fish formerly in the inactive net condition learned to avoid the moving net. In the second study, spatial discrimination learning was assessed. Zebrafish were trained on a right-left position discrimination to avoid the active net. Zebrafish showed significant improvement in escape responses over six sessions of training with three trials per session. In the third study, red-blue non-spatial discrimination learning was assessed. There was a significant improvement over the first six training sessions. With the reversal of contingencies, there was a significant decline of performance. With continued training, the fish again significantly improved avoidance. These studies found an effective motivational stimulus and procedure for studying escape behavior in zebrafish; a procedure whereby zebrafish would learn both spatial and non-spatial discrimination. These methods are being developed to help determine the functional importance of molecular events during zebrafish neurodevelopment.

Abstract: Knowledge of how animals manage their conflicts is critical for understanding the dynamics of social systems. During the last two decades research on gregarious animals, especially primates, has focused on the mechanisms of conflict management, mainly on friendly postconflict reunions (also called `reconciliation') in which former opponents exchange affiliative behaviour soon after an aggressive conflict. Our aim in this paper is to present a framework in which the costs and benefits of friendly postconflict reunions, both for each individual opponent and for their mutual relationship, are used to predict the patterning of postconflict resolution mechanisms in other gregarious animals. The framework predicts the occurrence of postconflict reunions in species that live in stable social units, have individualized relationships, and experience postconflict hostility, but especially in those in which intragroup aggression disrupts valuable relationships. The critical issue is whether aggressive conflicts occur between cooperative partners and whether the level of aggression is sufficient to jeopardize the benefits associated with such valuable relationships. We conclude by proposing four research priorities to evaluate the role of friendly reunions in negotiating relationships and the way they are themselves influenced by asymmetries in partner value and biological market effects. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.

Abstract: Abstract Analysis of salivary cortisol is increasingly used to assess stress responses in horses. Since spontaneous or experimentally induced increases in cortisol concentrations are often relatively small for stress studies proper controls are needed. This requires an understanding of factors affecting salivary cortisol over longer times. In this study, we have analysed salivary cortisol concentration over 6 mo in horses (n = 94) differing in age, sex, reproductive state and housing. Salivary cortisol followed a diurnal rhythm with highest concentrations in the morning and a decrease throughout the day (P < 0.001). This rhythm was disrupted in individual groups on individual days; however, alterations remained within the range of diurnal changes. Comparison between months showed highest cortisol concentrations in December (P < 0.001). Cortisol concentrations increased in breeding stallions during the breeding season (P < 0.001). No differences in salivary cortisol concentrations between non-pregnant mares with and without a corpus luteum existed. In stallions, mean daily salivary cortisol and plasma testosterone concentration were weakly correlated (r = 0.251, P < 0.01). No differences in salivary cortisol between female and male young horses and no consistent differences between horses of different age existed. Group housing and individual stabling did not affect salivary cortisol. In conclusion, salivary cortisol concentrations in horses follow a diurnal rhythm and are increased in active breeding sires. Time of the day and reproductive state of the horses are thus important for experiments that include analysis of cortisol in saliva.

Abstract: tEye and limb preferences were scored in the closest undomesticated relative of Equuscaballus using the same methods as used previously to study laterality in feral horses.Observations were made of 33 Przewalski horses (Equus ferus przewalskii) (male N = 20,female N = 13) living under natural social conditions on a large reserve in France. Signifi-cant left-eye/side biases were found in agonistic interactions within harem bands (M ± SEbias to left 58% ± 0.01 for threats, P < 0.001; 68% ± 0.05 for attacks; P < 0.001) and in stallionfights (threats, 52% ± 0.01 left, P < 0.001; attacks, 63% ± 0.02 left, P < 0.001): as many as 80%of the horses were significantly lateralized in attack responses within harem bands. Lat-erality of vigilance was measured as lifting up the head from grazing and turning it to theleft or right side: a directional bias to the left was found (M ± SE 53% ± 0.02 left, P < 0.001).Side bias in reactivity was calculated as the percent of head lifts above the level of thewithers on the left or right side and this was also left side biased (M ± SE 73% ± 0.03 left,P < 0.001). These results indicate right-hemisphere specialization for control of aggressionand responses to novelty. The left bias in attack scores within harem bands was strongerin males than females (P = 0.024) and in immature than adult horses (P = 0.032). Immaturehorses were also more strongly lateralized than adults in vigilance scores (P = 0.022), whichmay suggest that experience reduces these side biases. Our results show that Przewalskihorses exhibit left eye preferences, as do feral horses, and do so even more strongly thanferal horses. Considering feral and Przewalski horses together, we deduce that ancestralhorses had similar lateral biases. Also similar to feral horses, the Przewalski horses showedno significant forelimb preference at the group level or in the majority of horses at theindividual level, confirming the hypothesis that previously reported limb preferences indomestic breeds are entrained or generated by breed-specific selection.

Abstract: The aim of this study was to establish some basic facts about weanling horse (Equus caballus) behaviour in a loose housing/paddock environment during winter. The behaviour of 10 foals (seven American Standardbred and three Finnish cold-blooded foals) was observed in a cold loose housing/paddock environment from December 2002 to March 2003. The time budget, circadian rhythm and effect of weather conditions on behaviour were examined. The foals were observed for a total of 23 24-h periods by video recording. The method used was instantaneous sampling (), where the locations of foals were noted at every 15 min along with the behaviour performed at that time. Temperature, humidity and wind speed were recorded three times a day. The foals spent 43.2 +/- 6.6% of the time in the sleeping hall (an insulated building with a deep-litter bed), 51.4 +/- 5.8% in the open paddock and 5.2 +/- 2.7% in the shelter (a two-sided, roofed entrance shelter in front of the sleeping hall). The time spent outdoors was greatest between the hours of 08:00 and 20:00, but the foals spent some time outdoors also at night. They spent most of the day eating hay (27.6 +/- 3.0%) (offered ad libitum), standing (25.5 +/- 2.8%) and resting (32.1 +/- 2.4%). The proportion of locomotive behaviour patterns was 5% of the observations. The foals in this study were able to perform species-specific behaviour patterns (resting, eating, being active) and to follow the natural circadian rhythm of these patterns. The behaviour of the foals did not change much as the temperature dropped from 0 to -20 [degree sign]C. The time spent in the sleeping hall did not increase greatly, nor the time spent eating, resting or lying close to each other (huddling). On the basis of their behaviour, the weanling horses did not seem to suffer from the cold environment.