Home << 1 2 3 4 5 6 7 8 9 10 >> [11–20]
List View
 | 
Citations
 | 
Details
   web
Records
Author Nakamaru, M.; Sasaki, A.
Title Can transitive inference evolve in animals playing the hawk-dove game? Type Journal Article
Year 2003 Publication Journal of Theoretical Biology Abbreviated Journal J. Theor. Biol.
Volume 222 Issue 4 Pages 461-470
Keywords Hawk-dove game; Ess; Transitive inference; Resource holding potential
Abstract What should an individual do if there are no reliable cues to the strength of a competitor when fighting with it for resources? We herein examine the evolutionarily stable strategy (ESS) in the hawk-dove game, if the opponent's resource-holding potential (RHP) can only indirectly be inferred from the outcome of past interactions in the population. The strategies we examined include the classical mixed strategy in which no information on past games is utilized, the `imprinting' strategy in which a player increases/decreases its aggressiveness if it wins/loses a game, the `immediate inference' strategy in which a player can infer the strength of those opponents it fought before, and the `transitive inference' strategy in which a player can infer the strength of a new opponent through a third party with which both players have fought before. Invasibility analysis for each pair of strategies revealed that (i) the transitive-inference strategy can always invade the mixed strategy and the imprinting strategy, and itself refuses invasion by these strategies; (ii) the largest advantage for transitive inference is achieved when the number of games played per individual in one generation is small and when the cost of losing an escalated game is large; (iii) the immediate inference, rather than the transitive inference, can be an ESS if the cost of fighting is small; (iv) a strong linear ranking is established in the population of transitive-inference strategists, though it does not perfectly correlate to the ranking by actual RHPs. We found that the advantage of the transitive inference is not in its ability to correct a misassessment (it is actually the worst in doing so), but in the ability of quickly lining up either incorrect or correct assessments to form a linear dominance hierarchy.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved (up) no
Call Number refbase @ user @ Serial 601
Permanent link to this record
 
 
Author Seyfarth, R.M.; Cheney, D.L.
Title Meaning and emotion in animal vocalizations Type Journal Article
Year 2003 Publication Annals of the New York Academy of Sciences Abbreviated Journal Ann N Y Acad Sci
Volume 1000 Issue Pages 32-55
Keywords Acoustics; *Affect; Animals; Behavior, Animal; *Intention; Posture; Sound Spectrography; *Vocalization, Animal
Abstract Historically, a dichotomy has been drawn between the semantic communication of human language and the apparently emotional calls of animals. Current research paints a more complicated picture. Just as scientists have identified elements of human speech that reflect a speaker's emotions, field experiments have shown that the calls of many animals provide listeners with information about objects and events in the environment. Like human speech, therefore, animal vocalizations simultaneously provide others with information that is both semantic and emotional. In support of this conclusion, we review the results of field experiments on the natural vocalizations of African vervet monkeys, diana monkeys, baboons, and suricates (a South African mongoose). Vervet and diana monkeys give acoustically distinct alarm calls in response to the presence of leopards, eagles, and snakes. Each alarm call type elicits a different, adaptive response from others nearby. Field experiments demonstrate that listeners compare these vocalizations not just according to their acoustic properties but also according to the information they convey. Like monkeys, suricates give acoustically distinct alarm calls in response to different predators. Within each predator class, the calls also differ acoustically according to the signaler's perception of urgency. Like speech, therefore, suricate alarm calls convey both semantic and emotional information. The vocalizations of baboons, like those of many birds and mammals, are individually distinctive. As a result, when one baboon hears a sequence of calls exchanged between two or more individuals, the listener acquires information about social events in its group. Baboons, moreover, are skilled “eavesdroppers:” their response to different call sequences provides evidence of the sophisticated information they acquire from other individuals' vocalizations. Baboon males give loud “wahoo” calls during competitive displays. Like other vocalizations, these highly emotional calls provide listeners with information about the caller's dominance rank, age, and competitive ability. Although animal vocalizations, like human speech, simultaneously encode both semantic and emotional information, they differ from language in at least one fundamental respect. Although listeners acquire rich information from a caller's vocalization, callers do not, in the human sense, intend to provide it. Listeners acquire information as an inadvertent consequence of signaler behavior.
Address Departments of Psychology and Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. seyfarth@psych.upenn.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0077-8923 ISBN Medium
Area Expedition Conference
Notes PMID:14766619 Approved (up) no
Call Number refbase @ user @ Serial 688
Permanent link to this record
 
 
Author Bergman, T.J.; Beehner, J.C.; Cheney, D.L.; Seyfarth, R.M.
Title Hierarchical classification by rank and kinship in baboons Type Journal Article
Year 2003 Publication Science (New York, N.Y.) Abbreviated Journal Science
Volume 302 Issue 5648 Pages 1234-1236
Keywords Animals; Animals, Wild; Botswana; *Cognition; Family; Female; *Hierarchy, Social; Language; *Papio/psychology; Social Dominance; Vocalization, Animal
Abstract Humans routinely classify others according to both their individual attributes, such as social status or wealth, and membership in higher order groups, such as families or castes. They also recognize that people's individual attributes may be influenced and regulated by their group affiliations. It is not known whether such rule-governed, hierarchical classifications are specific to humans or might also occur in nonlinguistic species. Here we show that baboons recognize that a dominance hierarchy can be subdivided into family groups. In playback experiments, baboons respond more strongly to call sequences mimicking dominance rank reversals between families than within families, indicating that they classify others simultaneously according to both individual rank and kinship. The selective pressures imposed by complex societies may therefore have favored cognitive skills that constitute an evolutionary precursor to some components of human cognition.
Address Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA. thore@sas.upenn.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1095-9203 ISBN Medium
Area Expedition Conference
Notes PMID:14615544 Approved (up) no
Call Number refbase @ user @ Serial 689
Permanent link to this record
 
 
Author Seyfarth, R.M.; Cheney, D.L.
Title Signalers and receivers in animal communication Type Journal Article
Year 2003 Publication Annual review of psychology Abbreviated Journal Annu Rev Psychol
Volume 54 Issue Pages 145-173
Keywords Affect; *Animal Communication; Animals; Arousal; Auditory Perception; Motivation; *Social Behavior; Social Environment; Species Specificity; *Vocalization, Animal
Abstract In animal communication natural selection favors callers who vocalize to affect the behavior of listeners and listeners who acquire information from vocalizations, using this information to represent their environment. The acquisition of information in the wild is similar to the learning that occurs in laboratory conditioning experiments. It also has some parallels with language. The dichotomous view that animal signals must be either referential or emotional is false, because they can easily be both: The mechanisms that cause a signaler to vocalize do not limit a listener's ability to extract information from the call. The inability of most animals to recognize the mental states of others distinguishes animal communication most clearly from human language. Whereas signalers may vocalize to change a listener's behavior, they do not call to inform others. Listeners acquire information from signalers who do not, in the human sense, intend to provide it.
Address Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. seyfarth@psych.upenn.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0066-4308 ISBN Medium
Area Expedition Conference
Notes PMID:12359915 Approved (up) no
Call Number refbase @ user @ Serial 690
Permanent link to this record
 
 
Author McDonnell, S.M. (ed)
Title The Equid Ethogram: A Practical Field Guide to Horse Behavior Type Book Whole
Year 2003 Publication Abbreviated Journal
Volume Issue Pages
Keywords
Abstract
Address
Corporate Author Thesis
Publisher Eclipse Press Place of Publication Lexington, Kentucky Editor McDonnell, S.M.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 978-1581500905 Medium
Area Expedition Conference
Notes Approved (up) no
Call Number refbase @ user @ Serial 711
Permanent link to this record
 
 
Author Call, J.; Brauer, J.; Kaminski, J.; Tomasello, M.
Title Domestic dogs (Canis familiaris) are sensitive to the attentional state of humans Type Journal Article
Year 2003 Publication Journal of comparative psychology (Washington, D.C. : 1983) Abbreviated Journal J Comp Psychol
Volume 117 Issue 3 Pages 257-263
Keywords Animals; *Appetitive Behavior; *Attention; *Bonding, Human-Pet; *Concept Formation; Cues; Dogs/*psychology; Female; Humans; *Inhibition (Psychology); Male; Nonverbal Communication
Abstract Twelve domestic dogs (Canis familiaris) were given a series of trials in which they were forbidden to take a piece of visible food. In some trials, the human continued to look at the dog throughout the trial (control condition), whereas in others, the human (a) left the room, (b) turned her back, (c) engaged in a distracting activity, or (d) closed her eyes. Dogs behaved in clearly different ways in most of the conditions in which the human did not watch them compared with the control condition, in which she did. In particular, when the human looked at them, dogs retrieved less food, approached it in a more indirect way, and sat (as opposed to laid down) more often than in the other conditions. Results are discussed in terms of domestic dogs' social-cognitive skills and their unique evolutionary and ontogenetic histories.
Address Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany. call@eva.mpg.de
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. : 1983 Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0735-7036 ISBN Medium
Area Expedition Conference
Notes PMID:14498801 Approved (up) no
Call Number refbase @ user @ Serial 713
Permanent link to this record
 
 
Author Stoinski, T.S.; Whiten, A.
Title Social learning by orangutans (Pongo abelii and Pongo pygmaeus) in a simulated food-processing task Type Journal Article
Year 2003 Publication Journal of comparative psychology (Washington, D.C. : 1983) Abbreviated Journal J Comp Psychol
Volume 117 Issue 3 Pages 272-282
Keywords *Animal Communication; Animals; *Feeding Behavior; Female; *Imitative Behavior; Male; Pongo pygmaeus/*psychology; Problem Solving; Psychomotor Performance; Social Environment; Species Specificity; *Transfer (Psychology)
Abstract Increasing evidence for behavioral differences between populations of primates has created a resurgence of interest in examining mechanisms of information transfer between individuals. The authors examined the social transmission of information in 15 captive orangutans (Pongo abelii and Pongo pygmaeus) using a simulated food-processing task. Experimental subjects were shown 1 of 2 methods for removing a suite of defenses on an “artificial fruit.” Control subjects were given no prior exposure before interacting with the fruit. Observing a model provided a functional advantage in the task, as significantly more experimental than control subjects opened the fruit. Within the experimental groups, the authors found a trend toward differences in the actual behaviors used to remove 1 of the defenses. Results support observations from the wild implying horizontal transfer of information in orangutans and show that a number of social learning processes are likely to be involved in the transfer of knowledge in this species.
Address Department of Primate Research, Zoo Atlanta, Atlanta, GA 30315, USA. tstoinski@zooatlanta.org
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0735-7036 ISBN Medium
Area Expedition Conference
Notes PMID:14498803 Approved (up) no
Call Number refbase @ user @ Serial 737
Permanent link to this record
 
 
Author Wilson, D.A.; Stevenson, R.J.
Title The fundamental role of memory in olfactory perception Type Journal Article
Year 2003 Publication Trends in Neurosciences Abbreviated Journal Trends. Neurosci.
Volume 26 Issue 5 Pages 243-247
Keywords olfactory perception mammals
Abstract Current emphasis on odorant physiochemical features as the basis for perception largely ignores the synthetic and experience-dependent nature of olfaction. Olfaction is synthetic, as mammals have only limited ability to identify elements within even simple odor mixtures. Furthermore, olfaction is experience-bound, as exposure alone can significantly affect the extent to which stimuli can be discriminated. We propose that early analytical processing of odors is inaccessible at the behavioral level and that all odors are initially encoded as `objects' in the piriform cortex. Moreover, we suggest that odor perception is wholly dependent on the integrity of this memory system and that its loss severely impairs normal perception.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved (up) no
Call Number refbase @ user @ Serial 795
Permanent link to this record
 
 
Author Pusey, A. E.; Packer, C.
Title The Ecology of relationships Type Book Chapter
Year 2003 Publication Behavioural Ecology Abbreviated Journal Behav. Ecol.
Volume Issue Pages 254 -283
Keywords
Abstract
Address
Corporate Author Thesis
Publisher Blackwell Scientific Publication Place of Publication Oxford Editor Krebs, J.R.; Davis, N.B.;
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved (up) no
Call Number refbase @ user @ Serial 820
Permanent link to this record
 
 
Author Wasilewski A.
Title 'Friendship' in ungulates? – Sociopositive relationships between non-related herd members of the same species Type Manuscript
Year 2003 Publication Abbreviated Journal
Volume Issue Pages
Keywords
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.
Address
Corporate Author Thesis Ph.D. thesis
Publisher University of Marburg Place of Publication Marburg Editor
Language German Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved (up) no
Call Number refbase @ user @ Serial 824
Permanent link to this record