| dc.description | This thesis concerns the ontogeny of vocal patterns in wolves, including their acoustic properties, contexts of expression and apparent functions. While it has long been recognized that wolves are among the most complex terrestrial social mammals and that their vocal behaviour contributes significantly to their social organization, objective and quantitative assessments of wolf vocal ontogeny have been lacking. In this study I have provided the first systematic evaluation of neonatal wolf vocalization patterns. Recordings were obtained from three litters of pups in a semi-natural, undisturbed den. The development of vocal behaviour during the pups' first six weeks of age was quantified using a multidimensional classification scheme. I catalogued 3396 sounds and 800 behavioural events and subjected them to detailed analyses. Vocalizations were divided into 11 classes based on their spectrographic structure. Properties used to distinguish vocal classes included: gross spectral type, duration and three frequency variables. Measures of frequency variation, inter-element-interval duration of sound series and relative amplitude were also taken for selected sounds. Eight vocal classes were quantified. Vocal classes were subdivided into three groups: early-appearing neonate-specific, early-appearing adult-structured and late-appearing adult-structured. Ontogenetic trends included changes in the relative proportion of specific vocal classes, decreases in fundamental frequency and combinations of specific sounds into patterns of non-random series. The behavioural context of vocal classes was examined with descriptive and statistical analyses of the relations between selected vocal classes and three behavioural categories: pup and adult behaviour at onset of pup vocal activity, and subsequent adult responses to vocalizations. The context of vocal classes distinguished as neonate-specific did not vary significantly with maturation, whereas the context of the adult-structured classes varied with changes in social and physical development. Interpretations of the expressive content and the function of pup vocal behaviour were based on the objective criteria used to describe behavioural changes in development. | en_US |
