Moving in concert: Social and migratory behaviour of dolphins and whales in the North Atlantic Ocean

Marine mammals have developed numerous behavioural adaptations to life in the ocean. Studying these behaviours, however, can be challenging. Cetaceans spend a large part of their life under water, are often difficult to find across the vast ocean, and their behaviour may change in response to the presence of the observer. Hence, many fundamental aspects of cetacean behaviour remain unknown. This thesis combines newly developed observational methods and recent advances in technology to study cetacean behaviour. This approach allows for investigation of the social context of individual behaviour and analysis of migratory behaviour in relation to large-scale ocean dynamics. The results shed new light on social foraging strategies and social organisation of deep-diving cetaceans and on the foraging behaviour of migratory baleen whales in the North Atlantic Ocean.