Blue whale

No animal in the fossil record or alive today is known to outweigh the blue whale. Adults reach roughly 30 m (98 ft) in length, and the heaviest estimates sit between about 170 and 190 tonnes. NOAA's sanctuary program points out that it was bigger than the dinosaurs ever were.

The title is well established. The upper weight is an estimate, and sources differ by about ten percent.

Context

Blue whales (Balaenoptera musculus) feed almost entirely on krill, small shrimp-like animals, and in feeding season a single whale takes in several tonnes of them a day. They gulp huge volumes of water and push it out through baleen plates that trap the krill.

Nobody can put a living whale on a scale, so the heaviest figures come from measurements and estimates, many of them dating from the whaling era when animals were cut up and weighed in sections. That is why the upper weight carries a range rather than one number. Length is easier to measure, and the roughly 30 m figure is widely quoted for the largest individuals.

Industrial whaling in the 20th century drove blue whales close to extinction, and the species has been protected internationally since the mid-1960s. Populations are recovering slowly in some oceans but remain far below their historic numbers, and the species is still listed as endangered.