Mammals break all the records for largest, longest, and heaviest animals on land and in the oceans.
The biggest land animals are African elephants, which can grow to 4 meters tall and weigh over 6 tonnes - that's over twice as tall as a human and as heavy as six large cars.
The biggest animal the world has ever known as the ocean-going blue whale - it can grow to 30 meters long and weigh up to 160 tonnes, which is six times as long as 25 times as heavy as an elephant.