Abstract: Earlier research indicates that stallions may supress interactions of their harem members, leading to less stable hierarchies and friendship bonds in harems compared to non-stallion groups. In this paper, the effect of the presense of a stallion on the social behaviour of mares was studied by comparing six harems containing stallions to four mixed sex groups not containing stallions. Both temporary and permanent harems were studied, giving the possibility to investigate the effect of group stability on social interactions. A significant linear hierarchy was found in all non-stallion groups that were used for comparison, while the hierarchies were only found to be linear in three of the six harems containing stallions (Landaus h', p < 0.05). Aggression rate was lower (t-test, p < 0.05) and fewer friendship bonds (G-test, p < 0.0001) were found within the harems, compared to the groups without stallions. Stallions seldom intervene directly in interactions between harem members. Thus, our results give support to the hypothesis that stallions may suppress interactions of harem members, but in a more indirect way than with direct interference. In addition, our results give support for earlier findings that aggression rate may be affected by group stability. We found a higher aggression rate in the temporary harems compared to the permanent harems (Kruskal–Wallis, p < 0.05) and in the temporary non-stallion group compared to the permanent non-stallion group. The results have significance for further research on social structure of mammals, and may be applied in management of domestic animals.

Abstract: Responses of horses towards fear-eliciting stimuli can have important consequences for both human and horse safety. This experiment was designed to investigate behavioural and heart rate (HR) responses of horses to novel visual, auditory and olfactory stimuli. Twenty-four 2-year-old, previously unhandled, stallions were habituated to receive a food reward from a container in a test arena. Each horse was exposed to three 2 min tests in a balanced design where in addition to the feed container, either a traffic cone (visual test), white noise (auditory test) or eucalyptus oil applied to the inside of the container (olfactory test) were used as the novel stimuli. Compared to the control, less time was spent eating during all tests. There was no difference in locomotion activity in the different test situations, but presentation of the novel visual and auditory stimuli elicited significantly increased HR responses in the horses, compared to their response to the arena without novel stimuli (control), whereas there was no increase in HR response to the olfactory stimulus. However, during the olfactory test, the horses had an increased number of eating bouts and became more vigilant towards their surroundings, whereas during the visual and auditory tests, more time was spent alert towards the stimulus. The horses also took significantly more steps backwards in response to the auditory test. The heart rate responses correlated between tests and reflect a non-differentiated activation of the sympathetic nervous system, while the behavioural responses were linked to the type of stimulus.

Abstract: The term `leadership' has been used in several different senses, resulting in very different ways of identifying leaders and apparently inconsistent conclusions on how leadership is determined in herbivores. We therefore propose the following definitions: (i) a leader is the individual that is consistently the one who initiates long-distance, spontaneous group movements toward a new feeding site and (ii) long-distance spontaneous group movements are movements which happen when an animal changes activity and location and is immediately followed by a similar change in activity and location by other members of the group. Using these definitions, we tested for consistency of movement order across time and situation within a group of fifteen 2-year-old heifers. We found that the same individual was recorded as the very first animal in 48% of movements toward a new feeding site and could therefore be identified as the `leader'. We also showed that movement order when the animals entered an experimental plot, or progressed slowly through the field during a grazing bout, did not produce the same result. This method, which enables us to identify leaders in groups of animals at pasture, should improve our knowledge of how leadership is determined in grazing herbivores.

Abstract: For the past decade, the Washington Park Zoo, Portland, Oregon, has had an active behavioral research program. The research department is both a zoo-supported research facility for visiting researchers and staff, and an educational facility that teaches practical behavioral research methods to undergraduates. The research education program utilizes students from any of a dozen local colleges and universities. Students receive academic credit for their participation. Active keeper-participation plays a major role in many research projects. Not only does keeper-cooperation facilitate research, but their knowledge of the individual animals often proves invaluable. In addition to involvement in student projects, keepers have also conducted their own research projects.

Abstract: Tail-biting and other harmful social behaviours are a common problem on pig farms. The aims of the current experiment were (1) to investigate the genetic component of harmful social behaviours such as tail-biting by assessing breed differences, and (2) to further investigate the reliability and predictability of a test, [`]the tail-chew test', previously identified as potentially being capable of predicting a pig's predisposition for tail- and ear-biting. The behaviour of three pig breeds (Large White (LW), Landrace (LR), Duroc (DR)), with 100 pigs per breed, was observed in a [`]tail-chew test', and by observing the performance of harmful social behaviour directed to pen mates in flat deck pens after weaning. The tail-chew test, carried out on two consecutive days pre-weaning, involved observing the behaviour of individual pigs towards two suspended ropes. Pigs were weaned at 28 days and the occurrence of harmful social behaviour was recorded 4 weeks later over 2 consecutive days (1 h per day) using a group [`]period occurrence' scanning method. Breed had a significant effect on rope-directed behaviour in the tail-chew test and on harmful social behaviour. DR pigs interacted with the ropes in the tail-chew test more often (median 23.0 vs 19.0 and 17.5 times in 20 min, P<0.001) and for longer (31.0 vs 20.0 and 23.2 s, P<0.001) than LR and LW pigs, respectively. Although not significantly different from LW, DR pigs tended to direct more total harmful social behaviour towards pen mates than the other breeds. In particular, DR were observed in more total pig-directed biting of pen mates (median 9.0 vs 6.0 and 7.0, P<0.01) than LR and LW, and tended to nose pen mates more often than the other breeds (13.0 vs 11.0 and 10.0, P=0.06). LR pigs bit the ears of pen mates less often than LW and DR (4.0 vs 5.0 and 6.0, P<0.001). Belly-nosing activity was low, with a median of 0 for all breeds, but LR belly-nosed pen mates more often than Durocs (interquartile ranges 0-2.0 vs 0-1.0 and 0-1.0, P<0.01). The behaviour observed in the tail-chew test on day 1 correlated significantly with that observed on day 2 of the test (e.g. frequency of rope-directed behaviour rs=0.380,P<0.01). There were significant but weak correlations between rope-directed behaviour and the performance of some harmful social behaviours. The significant breed differences indicate some genetic contribution to expression of harmful social behaviours. However, the tail-chew test was found to be of limited ability to predict tail- and ear-biting under commercial conditions.