| Summary: | Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 1994 Focal-animal sampling techniques developed for investigating social behaviour of terrestrial animals were adapted for studying captive belugas, providing quantitative descriptions of social relationships .among individuals. Five groups of captive belugas were observed, allowing a cross-sectional view of sociality in groups of diverse sizes and compositions. Inter-individual distances were used to quantify patterns of spatial association. A set of social behaviours for which actor and recipient could be identified was defined to characterize dyadic interactions. The mother-calf pair spent more time together, and interacted more often than adults. The calf maintained proximity with his mother; larger adults generally maintained proximity with smaller adults. Among adults, larger groups performed more kinds of behaviours and interacted at higher rates than smaller groups. Within dyads, the larger whale performed more aggressive behaviours and the smaller whale more submissive behaviours. Clear dominance relations existed in three groups, with larger whales dominant to smaller whales. Vocalizations of three groups were classified subjectively, based on aural impressions and visual inspection of spectrograms, but most signals appeared graded. Statistical analyses of measured acoustic features confirmed subjective impressions that vocalizations could not be classified into discrete and homogeneous categories. This work was supported by the Education Office of the Woods Hole Oceanographic Institution, an Ocean Ventures Fund award, two Coastal Research Center grants, a grant from the National Aquarium in Baltimore, and by NOAA National Sea Grant College Program Office, Department of Commerce, under Grant No. NA90-AA-D-SG480, WHOI Sea Grant project no. R/B-115-PD. Additional support was provided by ONR contract no. ...
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