Abstract: Pferde sind Fluchttiere. Ihr Fluchtinstinkt bewirkt, dass sie sich leicht erschrecken und auch in
diversen Situationen mit Flucht reagieren. Diese Tatsache ist den meisten Reitern bekannt,
nur ist es für den Menschen teilweise schwer, mit dieser Eigenschaft auszukommen und sie zu
verstehen oder gar nachzuvollziehen. So kommt es häufig zu Unfällen, die aus der Angst der
Pferde resultieren, jedoch vermeidbar gewesen wären, hätte man ankündigende Signale früher
erkannt. Des Weiteren kann die Angst eines Pferdes auch durch eine (Ver-) Weigerung,
bestimmte Dinge zu tun, sichtbar werden. Diese Weigerung wird in der Reiterei gerne als
„Bockigkeit“ und „Ungehorsam“ des Pferdes interpretiert und führt nicht selten zu einer
Bestrafung. Insgesamt kann man sagen, dass angstauslösende Reize und die Reaktionen des
Pferdes darauf oft falsch eingeschätzt oder falsch interpretiert werden und in der Folge auch
falsch damit umgegangen wird. Ein Grund dafür ist sicher das fehlende Wissen über das
Verhalten des Pferdes. Mit der vorliegenden Diplomarbeit soll ein Beitrag geleistet werden,
das Pferd in seinem Angstverhalten besser zu verstehen. Ziel der Arbeit war es, das Verhalten
des Pferdes bei verschiedenen Intensitäten von Angst zu untersuchen. Des Weiteren wurden
Methoden untersucht, mit denen man die Angst von Pferden vor bestimmten Reizen und
Situationen potentiell lindern kann, was letztendlich auch der Unfallvorbeugung dient.
Die vorliegende Diplomarbeit wurde am Haupt- und Landesgestüt Marbach durchgeführt; 24
Junghengste standen hierfür zur Verfügung. Darunter waren 18 Deutsche Warmblüter, 3
Vollblutaraber und 3 Schwarzwälder Füchse (Kaltblüter), somit war auch ein Rassenvergleich
möglich.
In einem ersten Teil der Arbeit wurde untersucht, wie sich Angst bei Pferden äußert. Hierfür
wurde ausgenutzt, dass Pferde ganz generell vor unbekannten, neuen Gegenständen Angst
haben (= Neophobie). Zur Angstauslösung dienten als Konfrontationsgegenstände ein
Sonnenschirm und eine Plastikplane. Beide Gegenstände waren für die Testpferde unbekannt.
Das Verhalten sowie die Herzrate der Tiere wurden während aller Versuche beobachtet und
quantifiziert. Nacheiner ersten Konfrontation wurden die Pferde an die Objekte gewöhnt
(Extinktionstraining = Angstlöschung) und beobachtet welche Verhaltensymptome sich
während dieser Gewöhnung (= Verlust der Neophobie) verändern. Die Hypothese war, dass
tatsächliche Angstsymptome während der Gewöhnung immer seltener zu beobachten sind.
Zusammenfassung III
Als Verhaltensweisen für Angst konnten Ausweichbewegungen und Flucht, Lautäußerungen
(Prusten und Schnauben), das Anspannen der Halsmuskulatur sowie das Vordrücken der
Oberlippe identifiziert werden. Darüber hinaus wurde gezeigt, dass Abstufungen im
Angstverhalten möglich sind: Bei sehr hohem Angstlevel sind Fluchtreaktionen zu
beobachten. Bei mittlerem Angstlevel treten Ausweichbewegungen im Schritt und
Lautäußerungen (Prusten und Schnauben) auf, bei geringem Angstlevel wird die
Halsmuskulatur angespannt und die Oberlippe vorgedrückt.
Im Zweiten Teil der Arbeit sollten verschiedene Methoden zur Angst-Extinktionauf ihre
Wirksamkeit hin untersucht werden. Verwendet wurde in verschiedenen Testgruppen die
Methode der Desensibilisierung (d.h. leichte, schrittweise stärker werdende Exposition
gegenüber dem angstauslösenden Reiz), die Desensibilisierung mit Gegenkonditionierung
(positive Verstärkung) durch Streicheln bzw. Reiben des Halses und die Desensibilisierung
mit Gegenkonditionierung durch Futterbelohnung. Als Kontrollgruppe dienten Pferde, die
ohne eine Konfrontation mit dem angstauslösenden Reiz nur über den Versuchplatz geführt
wurden.
Während des Extinktionstrainings konnte beobachtet werden, dass die Desensibilisierung mit
Gegenkonditionierung zu einer schnelleren Extinktion führt als ohne Gegenkonditionierung.
Allerdings zeigte ein Vergleich mit der Kontrollgruppe, die das Extinktionstraining nicht
erfahren hatte, den gleichen Verlust an Angstverhalten wie die Gruppen mit Extinktionstraining.
Dieses Ergebnis wurde so interpretiert, dass die wiederholte Exposition gegenüber
angstauslösenden Reizen bei den durchgeführten Verhaltenstests zwar eine Rolle spielt, doch
dass auch allein die Beschäftigung mit den Tieren zu einem Verlust von Angstverhalten führt
(wahrscheinlich auch aufgrund eines wachsenden Vertrauens zur Führperson, die über das
komplette Experiment hin die Gleiche blieb).

Abstract: http://www.staff.uni-marburg.de/~z-phylog/wisstaff/wasi-sum.htm
Summary
* The quantitative study presented here demonstrates and verifies for ungulates the existence of social bonds, which in humans are termed 'friendships'. Whereas 'friendships' in non-human primates have become increasingly accepted over the past 30 years, their existence in non-primates remained as yet to be proved.
* The investigation was conducted on ungulates, because like primates the majority of their species are highly social; at the same time they are phylogenetically distant to the primates. To date, research into the social behaviour of ungulates in general, and of domestic species in particular, focuses predominantly on agonistic (socionegative) components, such as conflicts and resulting dominance hierarchies; sociopositive behaviours have been largely neglected.
As a consequence, previous evidence in favour of 'friendships' among ungulates remained largely anecdotal. Studies explicitly investigating sociopositive relationships among herd members are rare and typically confound bonds based on 'friendships' with reproductive relationships (kinship and sexually motivated bonds).
* Of each of the two large ungulate orders two species were investigated: horses and donkeys (Perissodactyla, Equidae) and sheep and cattle (Artiodactyla, Bovidae). The comparative, individual-based (and hence highly discriminative) longitudinal approach addressed all three levels of social organisation: associations, interactions and bond patterns within social units. Due to its systematic, quantitative, individual-based and comparatively broad design, this work may be considered to some degree a 'pioneering study'. As a consequence, a substantial amount of time and effort was required, particularly with respect to developing methods for the collection and analysis of data.
* Two reasons led to conducting this study on domestic ungulates: For farm animals information about who is related to whom is usually readily available, facilitating discrimination between friendship and kinship. Furthermore, successful proof of 'friendships' among ungulates would imply practical consequences for animal husbandry, since a social environment accommodating the animals' psychosocial needs is an essential prerequisite for their well-being (ethical reasons for animal protection) and ultimately results in higher productivity and hence economic efficiency (anthropocentric reasons for animal protection).
* Field research was conducted in England. Cattle and sheep were studied under commercial husbandry conditions, whereas appropriately large herds of horses and donkeys could only be found at a sanctuary.
* Two to three herds of each of the four species, namely cattle, sheep, donkeys and horses, comprising 11 to 60 members (average herd size approx. 25) were studied in two consecutive years (1996: 36 weeks, 1997: 28 weeks). The herds of cattle mainly consisted of subadult females, whereas those of the other species were predominantly composed of adults. Equids were kept in mixed-sex herds of mares and geldings (castrated males); the bachelor flocks of sheep consisted of 'intact' males (rams). The data presented here are based on 234 individuals and approximately 1500 hours of observation.
* Since even human social psychology provides neither a consistent definition nor a universally applicable terminology, it was necessary to establish a generally valid, precise definition of 'friendship'. Care was taken to exclude characteristics containing a bias as to the function of friendships (criteria were limited to those regarding contents and form). The definition contains all relevant criteria including those necessary for discrimination against alternative sociopositive relationships.

Friendship is defined as a voluntary, reciprocal, non-reproductive bond between individuals. It is primarily dyadic and carries a subjective value to both participants. Friendship is characterised by positive affect ('affection') and is expressed in a consistent inter-individual preference.
This definition is applicable to social relationships among both human and non-human animals, as well as interspecific relationships.
* Two types of parameters were used as indicators of 'friendship': frequency of spatial proximity (nearest neighbours; consistent neighbour preferences as a reflection of associations) and frequencies of different spontaneous as well as experimentally induced sociopositive interactions. For different reasons, of the four kinds of interactions (social grooming s.l., resting in physical contact, sharing limited feed, documenting behaviours s.l.) only grooming and feed sharing proved reliable.
* Aspects of the animals' spontaneous behaviour were recorded for all herds and in both years, whereas husbandry conditions demanded that complementary experiments be restricted to a few selected herds only. Data were collected using different Sampling and Recording Techniques, which were usually combined for maximum efficiency (e.g. Scan Sampling with nearest neighbour data, Ad libitum Sampling and Continuous Recording with sociopositive interactions).
* Data were subjected to an extensive statistical analysis. In addition to commonly used uni- and bivariate methods (Binomial and Chi-Square Goodness-of-Fit Tests, bivariate Correlations and Mantel Tests) a number of multivariate statistics were applied (Multidimensional Scaling, hierarchical Cluster Analysis, partial Correlations and multiple Mantel-Tests). Dyadic data are best represented as matrices; matrix data, however, pose the difficulty of partial interdependence, requiring Randomisation Tests (such as the one developed by Mantel) for their analysis. The complexity and amount of neighbour data required the development and optimisation of a 'customised' evaluation software (NENESYS = NEarest NEighbour SYstematic Standardisation programme) in close interdisciplinary cooperation with computer scientists and mathematicians.
* Seven different aspects of 'ungulate friendships' were addressed. The presented results differ in extent and depth.
1. Demonstration and verification of friendships in ungulates
2. Quantification of inter-individual preferences
3. Situation-specific aspects of these preferences
4. Dynamics and duration of friendships
5. Asymmetry within the relationships
6. Conditions enhancing friendships
7. Functions of animal friendships
* All four species expressed distinct inter-individual ('personal') preferences both for certain neighbours and for specific partners for sociopositive interactions. Endeavouring to present conservative and hence reliable assessments, only those neighbour preferences exceeding a threshold criterion were considered as associations. As the set-up of the study ensured that these associations met the criteria outlined in the definition of 'friendship' by excluding alternative bases for bonds (such as kinship and sexual motivation = reproductive relationships), the first explicit attempt at verifying the existence of friendship can be considered successful for all four species of ungulates examined. As a consequence, the concept of 'friendship' needs to be extended beyond the order of primates.
* Due to methodological reasons, the frequencies of interactions are only semi-quantitative and hence can be compared within herds only.
Frequencies of spatial proximity, on the other hand, provide a fully quantitative indicator, enabling direct comparisons across species, between different herds of the same species and between individuals. Due to the 'spatial limitations' of this thesis, it mainly focuses on inter-species comparisons.
With the exception of donkeys, the species could be arranged in sequence of increasing values of three parameters characterising their associative structure: maximum strength of association, maximum group size and proportion of herd members associated in distinct groups. Cattle showed the lowest values in all three parameters, sheep were intermediate, and horses reached the highest values. In these three species the strength of their associations was positively related to group size and the proportion of individuals associated in distinct groups. The donkeys did not fit this pattern: On the one hand, their association pattern comprised the lowest proportion of associated members and the smallest groups (pairs); on the other hand, these pairs exhibited very strong associations.
* Comparing inter-individual preferences across up to four different situations clear interspecific differences became evident. Some of these were greater between species of the same order than between orders.
The comparison of structures of association during grazing to those during resting, revealed two distinct patterns: Herds of horses and sheep flocks divided themselves into separate, usually mutually exclusive and independent groups and their associations corresponded greatly in both situations. Donkeys and cattle, on the other hand, formed diffuse, incomplete associative networks. The proportion of associations corresponding in both situations was far lower than in horses and sheep.
In all four species frequencies of social grooming s.l. (sheep are generally believed not to engage in social grooming, but see below) were compared to proximity frequencies during grazing and resting; and additionally to frequencies of feed sharing in the equid species.
Whereas horses restricted their sociopositive interactions entirely (grooming) or mostly (feed sharing) to members of their own group, cattle showed very little if any correspondence between partner preferences when grazing, resting and grooming. Donkeys spread their preferences widely across herd members, 'typically' approaching individuals for grooming with whom they were not associated during either grazing or resting. Considering their patterns of feed sharing, two different types of behaviour became evident: Pairs of donkeys that were closely associated during both grazing and resting, preferentially shared feed between them, whereas the remaining herd members did not discriminate between associates and non-associates when sharing feed. For sheep the findings of this study substantially increased the likelihood that unidirectional head rubbing and reciprocal cheek-to-cheek contact serve to strengthen 'personal' bonds and reduce tension – two functions generally attributed to social grooming. Both behaviours occurred mostly, but not exclusively, within groups of associated animals; these associations corresponded largely during grazing and resting.
* Results indicate that different types of social interactions and associations during different activities, respectively, may be particularly suited to initiate, consolidate and intensify friendships and occur particularly frequently during different phases of friendship formation and development. In horses, for instance, social grooming appears to some extent to be associated with the initiation of bonds, whereas resting in close proximity seems to strengthen newly formed relationships.
The longitudinal character of the study permitted to trace existing bonds over a maximum of 18 months. The duration of bonds in horses and sheep was comparable to findings of other authors for herds whose social networks resulted from a mixture of bonds based on both friendship and kinship; cattle relationships lasted shorter than described in the literature, while those in donkeys turned out to be approximately twice as long as had been documented to date.
* Aspects of asymmetry within dyadic relationships become particularly evident in grooming behaviours in bovids, which are typically performed unilaterally (social licking in cattle and head rubbing in sheep). Both behaviours can occur either spontaneously or as a consequence of solicitation.
* Addressing the question of factors potentially encouraging friendships, relationships between the degree of similarity with respect to some physical characteristics and nearest neighbour frequencies were found to be statistically significant. Cattle of similar age associated more closely, and horned rams preferred other individuals with horns as neighbours. The widely accepted preference of horses for associates of similar coat colour (and height) was not verified.
It remains to be decided whether (in addition to this preference for similar individuals) a preference based on complementary characteristics does exist.
* Following a critical review of the methodology employed, the benefits ungulates derive from friendships and possible applications for animal husbandry are discussed. Very little convincing evidence of a (direct) concrete, practical benefit was found. A psychological benefit in the form of social / emotional support, on the opposite, became highly probable.
Anecdotal evidence indicates, that situations causing a state of anxiety, may favour the initiation and intensification of friendships. Moreover, the study was able to statistically prove connection between (roughly) simultaneous introduction to a new herd (novel social environment) and persisting associations (as an indicator of friendships) in horses and sheep. These findings suggest that ungulate friendships provide a feeling of security. Social / emotional support among friends is predominantly given in a passive manner, e.g. in the form of – both literally and metaphorically – standing by a friend during conflicts with a third party, followed by social grooming with the friend. Social grooming has been shown by other authors to reduce physiological symptoms of stress. In addition, external signs of relaxation indicate a decrease in psychological tension. Hence, psychological support enhances the animal's physical health (and ultimately increases its biological fitness), providing an indirect practical benefit.
* Since all larger species of farm animals are highly social ungulates, the demonstration and verification of friendships implies consequences for husbandry practice. Intensive husbandry conditions are characterised by high animal densities, resulting in increased social stress, and grouping of animals of similar ages, which interferes with or prevents the formation and maintenance of bonds between kin. As friendships develop preferentially between individuals of similar age, they can be accommodated with relatively little effort when deciding about regrouping. The study presented here provides explicit recommendations to interested stockpersons on how to expeditiously and efficiently identify existing friendships and on which aspects to take into account when regrouping established herds or introducing new members.
* The different aspects of the study and their complex and often interwoven interrelations are condensed into a 'Regelkreismodell'. This model facilitates the generation of precise hypotheses for future research. Further detailed investigation into a variety of questions raised by this study seems in many ways promising and rewarding.
* The successful demonstration and verification of the existence of friendship in ungulates requires an extension of the 'concept of friendship' beyond the order of primates and encourages more detailed research into the bonding behaviour of other social vertebrates (e.g. elephants, dolphins, carnivores and also parrots).
* This extension demands a reinterpretation of some behaviours which so far have been unsatisfactorily or controversially classified, such as social head or horn rubbing in sheep, which has been mentioned occasionally, but received very little attention in the literature. Due to its occurrence during aggressive interactions, some authors consider horn or head rubbing to be agonistic. Others suppose the preorbital gland to play a significant role in this type of interaction and interpret head or horn rubbing as a 'respectful gesture' (adopting the dominant sheep's individual scent).
The study presents the first description of cheek-to-cheek contact in sheep. These cheek contacts are unequivocally sociopositive in nature. Since they are frequently associated with head rubbing, a third interpretation of head rubbing behaviour is offered by classifying both behaviours within the context of social grooming s.l.. More detailed examinations of these behaviours will be conducted as part of a research project into the evolution of the bovidae.