In the latter situation, lactation may last longer that 5 months. Behavior Humpback whales live in groups. They migrate seasonally from the tropics to the northern feeding grounds. In the tropics, they are found in dense aggregations on shallow banks. They tend to disperse more widely in deep waters then when in shallow water.
Humpbacks migrate between northern and southern latitudes in phase with the climactic cycle.
Migration is largely connected with the two functions of feeding and reproduction. They also tend to move through coastal waters during migrations when a land mass is in their direct route. Humpbacks appear in large numbers is subarctic waters in the spring and remain there until the summer. As the season advances, they become less numerous. The reason for humpback migration is thought to be that they seek warmer water in which to bring forth their young and that pairing and mating takes place at about the same time.