Abstract: Comparative experimental studies of imitative learning have focused mainly on primates and birds. However, cetaceans are promising candidates to display imitative learning as they have evolved in socioecological settings that have selected for large brains, complex sociality, and coordinated predatory tactics. Here we tested imitative learning in killer whales, Orcinus orca. We used a ‘do-as-other-does’ paradigm in which 3 subjects witnessed a conspecific demonstrator’s performance that included 15 familiar and 4 novel behaviours. The three subjects (1) learned the copy command signal ‘Do that’ very quickly, that is, 20 trials on average; (2) copied 100 % of the demonstrator’s familiar and novel actions; (3) achieved full matches in the first attempt for 8–13 familiar behaviours (out of 15) and for the 2 novel behaviours (out of 2) in one subject; and (4) took no longer than 8 trials to accurately copy any familiar behaviour, and no longer than 16 trials to copy any novel behaviour. This study provides experimental evidence for body imitation, including production imitation, in killer whales that is comparable to that observed in dolphins tested under similar conditions. These findings suggest that imitative learning may underpin some of the group-specific traditions reported in killer whales in the field.

Abstract: The ability of horses to learn through social observation may ease the implementation of new management systems, because the use of automatic feeders etc. by naive horses could be facilitated by observation of experienced horses. However, previous studies found no documentation for observational learning abilities in horses. This study aimed to investigate the ability of horses to learn an instrumental task from a familiar conspecific when social interaction was allowed during the demonstration. Two similar experiments were performed. In the first experiment, Observer horses (n=11) participated in ten successive demonstrations, where a trained Demonstrator opened an operant device by pushing a sliding lid aside with the muzzle in order to obtain a food reward. Immediately after the demonstrations the Observer horses were given the opportunity to operate the device alone. Control horses (n=11) were aware that the device contained food but were presented to the operant device without demonstration of the task. The learning criterion was at least two openings. Accomplishment of and latency to accomplish the learning criterion, and investigative behaviour towards the operant device were recorded. Five Observers and one Control, out of the eleven horses in each treatment group, accomplished the learning criterion. Even though this presents a high odds ratio (OR) in favour of the Observer treatment (OR=7.6), there was no significant difference between the treatment groups (P=0.15). Analysis of investigative behaviour showed, however, that the demonstrations increased the motivation of the Observer horses to investigate the device. Subsequently, a similar experiment was performed in a practical setting with 44 test horses (mixed age, gender and breed). We used the same operant device and the same number and type of demonstrations, although the horses were held on a loose rope to minimise aggression. In this second experiment, six of 23 Observer horses and five of 21 Control horses learned the instrumental task, representing no influence of the demonstration. Thus, this study did not demonstrate an ability of horses to learn an instrumental task through observation.

Abstract: Group-living animals are often faced with choosing between one or more alternative resource sites. A central question in such collective decision making includes determining which individuals induce the decision and when. This experimental and theoretical study of shelter selection by cockroach groups demonstrates that choices can emerge through nonlinear interaction dynamics between equal individuals without perfect knowledge or leadership. We identify a simple mechanism whereby a decision is taken on the move with limited information and signaling and without comparison of available opportunities. This mechanism leads to optimal mean benefit for group individuals. Our model points to a generic self-organized collective decision-making process independent of animal species.

Abstract: A group of brown lemurs was presented with one or two baited food-boxes requiring a specific type of motor response in order to be opened. Subsequently, four groups containing different combinations of experienced individuals from the original group and naive individuals were tested. Solutions to the problem and access to the food were recorded and considered in relation to social factors. In the original group, two adult males learned to open the boxes, with one male increasingly preventing the other from approaching. In the second group, with the subordinate male and certain females removed, the dominant male tolerated successful performances by a juvenile female. Group 3 consisted of three passive female participants from the original group and a naive female; one of the three original females now became the sole box-opener. The introduction of the subordinate male from the original group into the all-female group led to a sharing of box-opening by this subject and the skilled female. In the final group, intense aggression toward the skilled female by a new, naive adult male resulted in two previously passive females succeeding on some occasions. In lemurs, at least some `scroungers' appear able to learn to perform a new act when the social context permits.