At birth, calves are about 5m long and weigh more than one tonne. Hundreds of litres are drunk daily. Calves are nursed until they are one year old and about 8m long. Humpback whales mature in less than 10 years. Pods of mothers and calves are often escorted by an adult male.
Humpbacks sieve food from huge volumes of water using specialised fringed mouth-plates.
Bristle edges form a mesh to filter food from the water. These bristles give the baleen whales their scientific name Mysticetes, Greek for 'Moustached whale'. Humpbacks feed in the Antartic where food ios plentiful in preparation for their lengthy northern migration. Anecdotal evidence suggests opportunistic feeding of small bait fishmay occur along the migration path. Blubber reserves provide the bulk of their sustenance during migration.