Blue Whales are the biggest animals that live and have ever lived on the planet. Usually 30 metres long and weighing nearly 200 tonnes, they are heavier than fifty elephants put together and far bigger than any dinosaur that lived. Their tongue weighs more than one elephant, their heart is as big as a car and their veins are so big you can swim through them.

A Blue Whale is a fast-swimming animal that feeds mostly on krill. Krill is a small creature that is only a few centimetres long and one whale can eat 40 million of them in a day!

Blue Whales do not have teeth but huge bristle-like filters called baleen, which looks like a giant toothbrush hanging down from their mouths. Tthey use it to collect krill and other small creatures and plants from the ocean water.

Despite their enormous size, humans know little about them.