Abstract: Observational learning in chimpanzees and young children was investigated using an artificial fruit designed as an analog of natural foraging problems faced by primates. Each of 3 principal components could be removed in 2 alternative ways, demonstration of only one of which was watched by each subject. This permitted subsequent imitation by subjects to be distinguished from stimulus enhancement. Children aged 2-4 years evidenced imitation for 2 components, but also achieved demonstrated outcomes through their own techniques. Chimpanzees relied even more on their own techniques, but they did imitate elements of 1 component of the task. To our knowledge, this is the first experimental evidence of chimpanzee imitation in a functional task designed to simulate foraging behavior hypothesized to be transmitted culturally in the wild.

Abstract: This study investigated drinking behaviour of unhandled, semi-feral Dartmoor ponies. Aspects studied were drinking behaviour, latency to drink from novel unfamiliar drinkers after transport, preferences for different types of artificial water drinkers, effects of mixing with unfamiliar ponies and group size, on drinking behaviour, and the effect of a simulated market on the latency to drink. Ponies were tested in groups of three or six animals, or as individuals in test pens that were equipped with three water drinkers: bucket, automatic drinking bowl, flowing water trough. Behaviour was recorded using time-lapse video. An individual pony drank on average 10 l per day. Ponies also drank, but at a lower rate, during the night. The latencies to drink after 4.5 h of transport showed large variation, but most ponies drank within the first hour after being transported (all groups 80.5 ± 32.94 min, mean ± SEM). In the individual choice tests, the preferred drinkers were the bucket and the flowing water trough, but not the automatic drinking bowl (drinking time 25.2 ± 4.66, 11.5 ± 4.26, 2.4 ± 2.23 min for bucket, trough and bowl respectively, mean ± SEM; paired t-tests, bowl versus other drinkers, all tests p < 0.02). A possible reason for the avoidance of the automatic bowl was the noise it made when filling. After mixing a group of three ponies with a group of three unfamiliar animals, the ponies did not express their individual drinker preferences anymore. The use of the previously preferred bucket decreased significantly and the use of the initially, non-preferred, bowl increased significantly. This was likely caused by the fact that ponies were either intentionally or accidentally obstructing drinkers in certain areas of the pen and unfamiliar ponies did not want to push past them. In the simulated market, the differences in latencies to drink between ponies in the home pen and market groups did not reach significance. No significant effect of group size (groups of three versus six ponies) on drinking behaviour was detected. The results have implications for situations where only automatic water bowls are provided, such as during pony sales at livestock markets. Preventing ponies from expressing their drinking choice, either by offering non-preferred drinkers or by mixing with unfamiliar animals, could adversely affect their welfare especially if this happens in conjunction with other stressful events such as transport and markets, and potentially weaning.

Abstract: Abstract  The issue whether non-human primates have other-regarding preference and/or inequity aversion has been under debate. We investigated whether tufted capuchin monkeys are sensitive to others’ reward in various experimental food sharing settings. Two monkeys faced each other. The operator monkey chose one of two food containers placed between the participants, each containing a food item for him/herself and another for the recipient. The recipient passively received either high- or low-value food depending on the operator’s choice, whereas the operator obtained the same food regardless of his/her choice. The recipients were either the highest- or lowest-ranking member of the group, and the operators were middle-ranking. In Experiment 1, the operators chose the high-value food for the subordinate recipient more frequently than when there was no recipient, whereas they were indifferent in their choice for the dominant. This differentiated behavior could have been because the dominant recipient frequently ate the low-value food. In Experiment 2, we increased the difference in the value of the two food items so that both recipients would reject the low-value food. The results were the same as in Experiment 1. In Experiment 3, we placed an opaque screen in front of the recipient to examine effects of visual contact between the participants. The operators’ food choice generally shifted toward providing the low-value food for the recipient. These results suggest that capuchins are clearly sensitive to others’ reward and that they show other-regarding preference or a form of inequity aversion depending upon the recipients and the presence of visual contact.

Abstract: It has recently been reported that predator inspection is more likely to occur when a companion (i.e. the mirror image of the test animal) is visible on the left rather than on the right side of mosquitofish Gambusia holbrooki. This very unexpected outcome could be consistent with the hypothesis of a preferential use of the right eye during sustained fixation of a predator as well as of a preferential use of the left eye during fixation of conspecifics. We measured the time spent in monocular viewing during inspection of their own mirror images in females of six species of fish, belonging to different families--G. holbrooki, Xenotoca eiseni, Phoxinus phoxinus, Pterophyllum scalare, Xenopoecilus sarasinorum, and Trichogaster trichopterus. Results revealed a consistent left-eye preference during sustained fixation in all of the five species. Males of G. holbrooki, which do not normally show any social behaviour, did not exhibit any eye preferences during mirror-image inspection. We found, however, that they could be induced to manifest a left-eye preference, likewise females, if tested soon after capture, when some affiliative tendencies can be observed. These findings add to current evidence in a variety of vertebrate species for preferential involvement of structures located in the right side of the brain in response to the viewing of conspecifics.

Abstract: Abstract Evidence for behavioural and brain lateralisation is now widespread among the animal kingdom; lateralisation of limb use (pawedness) occurs in several mammals including both feral and domestic horses. We investigated limb preferences in 14 Quarter Horse during different motor tasks (walking, stepping on and off a step, truck loading and unloading). Population lateralisation was observed in two tasks: horses preferentially used their left forelimb during truck loading and stepping off a step. The results also revealed that horses showed higher scores for anxious behaviours during truck loading suggesting that the use of the left forelimb in this task may reflect the main role of the right hemisphere in control of behaviour during stressful situation.