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Olfactory and Behavioural Regulation of Territorial Aggression in Feral Rats (Rattus norwegicus)

<p> This thesis is primarily concerned with the problem of recognition among feral Norway rats. Wild rats are known to behave amicably in the presence of colony members and act in a stereotyped aggressive manner towards unfamiliar conspecifics in a territorial context. Previous reports suggest that identity is basically olfactory and is organized around colony-specific odors residing in the nesting material or the metabolic excretions of the male members of a colony.</p> <p> The first experiments in this study were attempts to replicate various reports concerning the maleability of clan odors, thereby giving a wild rat the olfactory characteristics of an alien group and, conversely, to alter a resident's odor such that he was no longer identifiable as a member of his original clan. Further experiments examined identifier and regulator functions of behavioural cues on social interaction subsequent to recognition. The interactions of unfamiliar rats on a mutually common terrain was studied, and compared with that of familiar rats paired on an uncommon territory. The final experiment investigated the functional nature of olfactory stimulation in these situations and compared the reactions of anosmic residents towards familiar and unfamiliar conspecifics.</p> <p> These experiments indicate that recognition is indeed an olfactory process but that identity is highly resistent to alteration. The identifier substance does not appear to be contained in either the nesting matter nor in a colony's urine or feces. Bond of familiarity are not specific to a common terrain and in most cases behavioural cues appear to control the onset and termination of fight behaviour following the olfactory identification. Studies of anosmic residents indicate that novel odors elicit aggressive tendencies while familiar odors are not inhibitors of aggression. The results suggest the presence of a specific male pheromone that is essential for the arousal of aggression while the topography of interaction is regulated largely by the reciprocal behaviours of the animals.</p> / Thesis / Master of Arts (MA)

Identiferoai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/20892
Date10 1900
CreatorsAlberts, Jeffrey R.
ContributorsGalef Jr., Bennet G., Psychology
Source SetsMcMaster University
Languageen_US
Detected LanguageEnglish
TypeThesis

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