Photos: CFP

Humpback whales were seen swimming off the coast of Port Stephens, New South Wales, Australia on Monday.

After a summer of feeding on krill in Antarctic waters, thousands of humpback whales have begun their 5,000-kilometer, three-month migration to the warmer waters of northern Australia where they will mate and give birth.

The humpback whale is a species of baleen whale. It can grow up to 16 meters long and weigh up to 30 tonnes.