.......................................................................................................................................... ii PREFACE.............................................................................................................................................. iii TABLE OF CONTENTS ....................................................................................................................... iv LIST OF TABLES ................................................................................................................................ vii LIST OF FIGURES.............................................................................................................................. viii GLOSSARY .......................................................................................................................................... xi ACKNOWLEDGMENTS.................................................................................................................... xiii DEDICATION..................................................................................................................................... xvi 1.GENERAL INTRODUCTION............................................................................................................. 1 1.1 Vocal learning .............................................................................................................................. 2 Mimicry and vocal learning......................................................................................................... 6 1.2 What do we know about vocal learning in belugas? ................................................................... 7 1.3 What do we know about beluga social structure? ....................................................................... 9 1.4 What do we know about the acoustic behaviour of belugas?.................................................... 12 1.5 Thesis objectives and organization ............................................................................................ 18 2.VOCAL DEVELOPMENT IN A BELUGA CALF (DELPHINAPTERUS LEUCAS).......................... 19 2.