Abstract: The social behaviour of two groups of Merino ewes and one group of Merino x Border Leicester ewes was studied. Each group comprised eight sheep, 15 months of age and, within each group, the animals were of similar liveweight. Dominance rankings were established at each test, but there was little consistency in ewe rank over time. Similarly, little consistency was found in ewe ranking for movement order between pens, and for exploratory and fear test rankings. However, with tests on movement orders, some consistency in the sheep which ranked first was shown. In the field, no aggression was seen while sheep were grazing and there were no occasions when ranking related to movement could be observed. There were short-term associations between pairs of sheep, but these occurred in less than half the individuals. Although the spatial distribution was not studied, the lack of long-term association between pairs would suggest that strong spatial preference does not occur. It is concluded that the social organization of single-age Merino and Merino x Border Leicester ewes is not based on dominance or leadership ranking nor on long-term associations between individuals.

Abstract: We compared the size of skeletal and ornamental traits, and asymmetries in bilateral skeletal traits, between victims of cannibalism, cannibals and bystanders within small groups of caged female White Leghorns at the time of cannibalistic attacks (i.e. injurious pecks resulting in bleeding). We hypothesised that victims of cannibalism have discernible morphological traits that predispose them to cannibalistic attack. We predicted that victims would have smaller skeletal traits (body length, ulna length, metatarsus length and width, toe length), lower body weight, poorer body condition, smaller combs and more asymmetrical bilateral skeletal traits than their flock mates. Contrary to our prediction, victims of cannibalistic attacks to the head/neck area (N=23) tended to have larger combs than their flock mates (Wilcoxon matched-pairs signed-ranks test, S=59, P=0.037, NS after sequential Bonferroni adjustment). Their cannibals were more asymmetrical than non-cannibalistic bystanders (metatarsus length, S=48, P=0.011 and composite asymmetry, S=62.5, P=0.002, significant after sequential Bonferroni adjustment). In agreement with our prediction, victims of cannibalistic attacks to other body parts (N=27), including the back, wings, rump, tail, cloaca, abdomen and toes, were more asymmetrical (composite asymmetry, S=78, P=0.022, significant after sequential Bonferroni adjustment) and tended to have lower body weights (S=79.5, P=0.029, NS after sequential Bonferroni adjustment) than their flock mates. Their cannibals did not differ in skeletal or ornamental traits from the non-participating bystanders. The results suggest that large combs either elicit attacks to the head and neck area or increase vulnerability to injury during such attacks. Attacks to other body parts appear to be directed towards birds with signs of weakness relative to their flock mates. In these attacks, there were no distinguishing features separating cannibals from bystanders, suggesting that the bystanders could all be potential cannibals.

Abstract: Capercaillie, a large species of grouse, are sometimes killed when they fly into high-tensile deer fences. A fence design which is lower or has a less rigid top section than conventional designs would reduce bird deaths, but such fences would still have to be deer-proof. The short-term behavioural responses of farmed red deer (Cervus elaphus) to fences of five designs, including four that were designed to be less damaging to capercaillie, were measured. Five deer were located on one side of a fence with a larger group (20 animals), from which they had been recently separated, on the other. The efficacy of fences in preventing deer from the small group from rejoining the larger group was also recorded. In addition to a conventional deer fence (C) the four new designs were, an inverted “L” shape (L), a fence with offset electric wire (E), a double fence (D) and a fence with four webbing tapes above (W). Four replicate groups of deer were each tested for 3 days with each fence design. Deer paced the test fence line relatively frequently (a proportion of 0.09 scan observations overall) but significantly less when deer were separated by fences E or C compared to L, W or D (overall difference between fence types, P<0.001). Deer separated by fence E spent significantly more time pacing perimeter fences than deer separated by fences of other types (overall difference between fence types, P<0.01) but deer separated by fence C maintained a low level of fence pacing overall. Analysis of behaviour patterns across the first day and the 3 days of exposure suggested that the novelty of the test fences, rather than the designs per se, influenced the behaviour of the deer. Over the course of the study, no deer crossed either C or L. Three deer crossed E and two deer crossed both W and D. On this basis, field testing, particularly of fence L, would be a useful next step.

Abstract: Social dominance is a multidimensional phenomenon occurring in all gregarious farm animals and finds its reflection in a dominance hierarchy. Hence, numerous studies have tried to analyse dominance relationships as well as to correlate outcoming results (mostly individual ranks) with other behavioural and/or physiological features of the animals. Although the concept of dominance, once established, has been developed continuously and several sociometric measures were cumulatively introduced, a consistent analysing approach has not been achieved, especially in farm animals. Thus, considerable inconsistencies in the used methodology may impair obtained results and interpretations. The present paper is a plea for a more standardised and complex approach when analysing dominance relationships, not only in farm animals. First, derived from a structural definition of dominance, we suggest in detail the preferably consistent use of appropriate sociometric measures at all social levels of analysis: the dyad as the starting level, the group as the highest level, and the individual as the basic level. Second, we applied this procedures in a case study to analyse social dominance in a group of dwarf goats (n=12) and pigs (n=10), respectively, to comparatively demonstrate benefits and problems of such an approach in two different farm animal species. It is concluded that the use of individual ranks is actually only reasonable when fundamental sociometric measures both at the dyadic level (e.g. percentage of dyads which have a significant asymmetric outcome) and at the group level (e.g. the strength of hierarchy) are successfully tested by statistical methods as also presented in this paper. The calculated sociometric measures deliver not only a more comprehensive “picture” of the social relationships within a group as simple ranks do, but also indicate possible reasons of differences in the behavioural development. For instance, whereas the dwarf goats maintained a quasi-linear dominance hierarchy over time with a high rate of overt agonistic behaviour, pigs after the establishment of their hierarchy showed a reduced agonistic behaviour which makes it questionable to calculate reliable sociometric measures. These species-dependent variations may be primarily caused by different kinds of the fighting behaviour in goats (i.e. ritualised, low costs) and pigs (i.e. more seriously, high costs). Overall, a more consistent and standardised approach of analysing social dominance in (farm) animals may improve the scientific value of single studies and makes it easier to compare various studies within a species and between species.

Abstract: Many of the signals that animals use to communicate transmit relatively large distances and therefore encompass several potential signallers and receivers. This observation challenges the common characterization of animal communication systems as consisting of one signaller and one receiver. Furthermore, it suggests that the evolution of communication behaviour must be considered as occurring in the context of communication networks rather than dyads. Although considerations of selection pressures acting upon signallers in the context of communication networks have rarely been expressed in such terms, it has been noted that many signals exchanged during aggressive interactions will transmit far further than required for information transfer between the individuals directly involved, suggesting that these signals have been designed to be received by other, more distant, individuals. Here we consider the potential for receivers in communication networks to gather information, one aspect of which has been termed eavesdropping. We show that male Betta splendens monitor aggressive interactions between neighbouring conspecifics and use the information on relative fighting ability in subsequent aggressive interactions with the males they have observed.