Abstract: Abstract One mechanism to resolve conflict among group members is third party intervention, for which several functions, such as kin protection, alliance formation, and the promotion of group cohesion have been proposed. Still, empirical research on the function of intervention behaviour is rare. We studied 40 cases of intervention behaviour in a field study on 13 semi-wild bachelor horses (Equus ferus przewalskii) in (a) standard social situations, and (b) when new horses joined the group (i.e. introductions). Only interventions in agonistic encounters were analysed. Eight of 13 animals directed intervention behaviour toward threatening animal in agonistic encounters of group members. One stallion was particularly active. The stallions did not intervene to support former group mates or kin and interventions were not reciprocated. In introduction situations and in standard social situations, the interveners supported animals which were lower in rank, but targeted, threatening animals of comparable social rank. After introductions, stallions received more affiliative behaviour from animals they supported and thus appeared to intervene for alliance formation. In standard social situations, interveners did not receive more affiliative behaviour from animals they supported and may primarily have intervened to promote group cohesion and to reduce social disruption within the group.

Abstract: Understanding how groups of individuals with different motives come to daily decisions about the exploitation of their environment is a key question in animal behaviour. While interindividual differences are often seen only as a threat to group cohesion, growing evidence shows that they may to some extent facilitate effective collective action. Recent studies suggest that personality differences influence how individuals are attracted to conspecifics and affect their behaviour as an initiator or a follower. However, most of the existing studies are limited to a few taxa, mainly social fish and arthropods. Horses are social herbivores that live in long-lasting groups and show identifiable personality differences between individuals. We studied a group of 38 individuals living in a 30-ha hilly pasture. Over 200 h, we sought to identify how far individual differences such as personality and affinity distribution affect the dynamic of their collective movements. First, we report that individuals distribute their relationships according to similar personality and hierarchical rank. This is the first study that demonstrates a positive assortment between unrelated individuals according to personality in a mammal species. Second, we measured individual propensity to initiate and found that bold individuals initiated more often than shy individuals. However, their success in terms of number of followers and joining duration did not depend on their individual characteristics. Moreover, joining process is influenced by social network, with preferred partners following each other and bolder individuals being located more often at the front of the movement. Our results illustrate the importance of taking into account interindividual behavioural differences in studies of social behaviours.

Abstract: Summary Reliable assessment of animal populations is a long-standing challenge in wildlife ecology. Technological advances have led to widespread adoption of camera traps (CTs) to survey wildlife distribution, abundance and behaviour. As for any wildlife survey method, camera trapping must contend with sources of sampling error such as imperfect detection. Early applications focused on density estimation of naturally marked species, but there is growing interest in broad-scale CT surveys of unmarked populations and communities. Nevertheless, inferences based on detection indices are controversial, and the suitability of alternatives such as occupancy estimation is debatable. We reviewed 266 CT studies published between 2008 and 2013. We recorded study objectives and methodologies, evaluating the consistency of CT protocols and sampling designs, the extent to which CT surveys considered sampling error, and the linkages between analytical assumptions and species ecology. Nearly two-thirds of studies surveyed more than one species, and a majority used response variables that ignored imperfect detection (e.g. presence?absence, relative abundance). Many studies used opportunistic sampling and did not explicitly report details of sampling design and camera deployment that could affect conclusions. Most studies estimating density used capture?recapture methods on marked species, with spatially explicit methods becoming more prominent. Few studies estimated density for unmarked species, focusing instead on occupancy modelling or measures of relative abundance. While occupancy studies estimated detectability, most did not explicitly define key components of the modelling framework (e.g. a site) or discuss potential violations of model assumptions (e.g. site closure). Studies using relative abundance relied on assumptions of equal detectability, and most did not explicitly define expected relationships between measured responses and underlying ecological processes (e.g. animal abundance and movement). Synthesis and applications. The rapid adoption of camera traps represents an exciting transition in wildlife survey methodology. We remain optimistic about the technology's promise, but call for more explicit consideration of underlying processes of animal abundance, movement and detection by cameras, including more thorough reporting of methodological details and assumptions. Such transparency will facilitate efforts to evaluate and improve the reliability of camera trap surveys, ultimately leading to stronger inferences and helping to meet modern needs for effective ecological inquiry and biodiversity monitoring.

Abstract: Die soziale Fellpflege wurde bei Equiden intensiv erforscht. Es stellte sich heraus, dass diverse Faktoren das Grooming-Verhalten beeinflussen können. Neben saisonalen Gegebenheiten sind dies vor allem soziale Faktoren, wie das Alter und Geschlecht der Tiere, die Hierarchie und Gruppenzusammensetzung sowie die Verwandtschaftsverhältnisse der Tiere untereinander. Diese Faktoren können sowohl bei der Häufigkeit der sozialen Fellpflege, als auch bei der Wahl des Partners eine entscheidende Rolle spielen. Zudem konnte gezeigt werden, dass auch das Aggressivitätslevel in einer Gruppe Einfluss auf das soziale Verhalten und die soziale Fellpflege nehmen kann. Inwiefern zwei Individuen, die sich häufig groomen, auch bevorzugt beieinander stehen, konnte bislang noch nicht eindeutig gezeigt werden, da es hierzu diverse Studien mit konträren Ergebnisse gibt. Dieser Aspekt sollte zukünftig dringend untersucht werden, da die beiden Datensätze häufig gemeinsam verwendet werden, um soziale Bindungen zu berechnen, ohne dass bislang ein eindeutiger Zusammenhang zwischen ihnen ermittelt werden konnte.
[Summary
Social grooming has been investigated intensively in Equids during the last years and several factors are known to influence the grooming behaviour. Beside seasonal conditions these are especially social factors as age and sex, hierarchy and group composition as well as kinship. These factors can affect the grooming frequencies and influence the choice of the grooming partner. Moreover, it could be demonstrated that the groups’
aggression level can influence the social behaviour and the grooming intensity. If individuals which show an increased grooming frequency often stand in close proximity as well, has not been affirmed, as, so far, no distinct correlation has been demonstrated. This aspect has to be investigated urgently, as both data sets are often used in combination for calculating social bonds.]

Abstract: Lateralization in horses, Equus caballus, has been reported at both motor and sensory levels. Here we investigated left- and right-nostril use in 12 jumper horses freely sniffing different emotive stimuli. Results revealed that during sniffing at adrenaline and oestrus mare urine stimuli, horses showed a clear right-nostril bias while just a tendency in the use of the right nostril was observed during sniffing of other odours (food, cotton swab and repellent). Sniffing at adrenaline and urine odours was also accompanied by increasing cardiac activity and behavioural reactivity strengthening the role of the right hemisphere in the analysis of intense emotion and sexual behaviour.