Whale Migration
Whale migration, like migration in any other animals, is a riskfull and energy-costly habit.
For any animals to migrate, particularly in long distances, the benefits have to overweigh the risks and the costs of energy. While birds for example migrate to higher latitudes for summer months since the insect concentrations are worth it, many whales migrate to warmer waters during winter months to mate and give birth to their young in warmer waters. During the summer, they migrate to cool waters towards the poles where there is lots of krill to eat.
Blue Whale Migration
Blue Whales migrate thousands of kilometres every year between their summer feeding grounds in higher latitudes, and their winter breeding grounds closer to the equator in warmer waters. When they migrate, they don't eat anything for months. Older whales migrate first while younger whales follow behind them. In warm waters, they mate, and pregnant females give birth, before they start the journey to colder waters again. In the cold waters of Arctic or Antarctic, they feed on krill which is plentiful during summer months.
Gray Whale Migration
There are two populations of Gray Whales, both in the Northern Hemisphere. The smaller - the western Pacific population travels from Kamtchatka Peninsula in Russia's far east to warm waters south of Korea and Japan during the winter months to mate and give birth to the young. The larger - the Eastern Pacific population travels about 10,000 km from Alaska to Mexico which is believed to be the longest yearly migration route in all mammals. Pregnant whales arrive first, give birth and leave latest, once the calves are ready for the journey.
Jorney of Humpbacks
Humpback Whales, just like Blue Whales, are found in both hemispheres. They, too, migrate long distances between their winter feeding grounds in higher latitudes, and summer breeding grounds in warmer waters closer to the equator. They travel quite slowly, and stop off in places along the road to rest and socialise. Older juveniles tend to travel first, then mature males and finally females with calves. Humpbacks are famous for their whale song while migrating, although other whales, e.g. some Blue Whales do sing too.
Dolphin Migration
Do dolphins migrate? Many species of dolphins move seasonally to find more abundant food and better water temperatures. This, however, is not migration, as migration by definition means annual movements between the same places in each end. Dolphin's movements are more nomadic than migratory, they don't move back and forwards between the same places. And unlike baleen whales, they don't move for the purpose of breeding, and they don't move anywhere near as long distances as do the baleen whales.
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