Blue whales eat krill - tiny, shrimp-like crustaceans that live throughout Earth's oceans. The huge whales can eat up to four tonnes of krill every day. Blue whales lunge through large swarms of krill ...

These colossal cetaceans often reach 30 metres in length and can weigh up to 180 tonnes - so they need to eat a lot to keep them swimming. But despite their enormous size, blue whales feed almost ...