A blue whale - its total lung capacity of 5,000 litres (1,320 US gal) is enough to inflate an estimated 2,000 party balloons.
It comes as a surprise to many people that Earth’s biggest ever creature wasn’t a dinosaur. In fact, the largest mammal ever, and indeed the largest animal ever, is very much alive and kicking today, or at least alive and flipping.
The blue whale (Balaenoptera musculus) can measure some 30 m (100 ft) long and weigh 200 tonnes (440,000 lb), though on average they tend to fall within 23–27 m (70–90 ft) and 100–150 tonnes (200,000–300,000 lb).
For a better grasp of their size, see the infographic below:
Of interest, find out which animals are record-holders at NationalZoo.si.edu.