Migrating is a part of every whales life, migrating to mate, stay warm and feed. Though some whales don't migrate, almost all of them do. Whales lives are almost like a schedule, half of the year they stay in their home, when that half of the years up they migrate to maybe the equator or the Artic regions. The reason whales do this is because where the whale lives year round there might be a food shortage or when they need to breed they are no other whales of that species of whale around, well what does the whale do? The whale will migrate to maybe a warm place were there is plenty of food or maybe another place were some other of it's species are, so it might breed and raise its young there if it meets good expectations for the mother. Migrating is a good way to escape predators, if for some reason the number of predators increased in a area the whale could migrate early to it's migration place and be safe.