Abstract: Horses (Equidae ) are believed to clearly demonstrate the links between ecology and social organization. Their social cognitive abilities enable them to succeed in many different environments, including those provided for them by humans, or the ones domestic horses encounter when escaping from their human care takers. Living in groups takes different shapes in equids. Their aggregation and group cohesion can be explained by Hamilton“s selfish herd theory. However, when an individual joins and to which group it joins appears to be an active individual decision depending on predation pressure, intra group harassment and resource availability. The latest research concerning the social knowledge horses display in eavesdropping experiments affirms the need for an extension of simple herd concepts in horses for a cognitive component. Horses obviously realize the social composition of their group and determine their own position in it. The horses exceedingly flexible social behavior demands for explanations about the cognitive mechanisms, which allow them to make individual decisions. ”Ecology conditions like those that favour the evolution of open behavioural programs sometimes also favour the evolution of the beginnings of consciousness, by favouring conscious choice. Or in other words, consciousness originates with the choice that are left open by open behavioural programs." Popper (1977)

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.]