Largest migrant

At up to 27 m (88 ft) long and weighing 160 tonnes (352,000 lb), the blue whale (Balaenoptera musculus) is not only the largest animal in the world but also the largest to migrate, travelling thousands of kilometres from their Arctic or Antarctic feeding grounds to the warmer winter breeding grounds in the tropics. Blue whales feed on the rich supply of krill available in the polar regions, but must make an annual migration to the equator to breed, as their calves – born with just a thin layer of blubber - need warm waters to survive.