Largest mammal

The largest mammal (and indeed the largest animal) on Earth based on weight is the blue whale (Balaenoptera musculus), which fully grown is around 20–30 m (65–100 ft) long and weighs c. 160 tonnes (176 tons). Even larger historical specimens have been documented by both length and weight.

Heaviest: A female blue whale weighing 190 tonnes (418,878 lb) and measuring 27.6 m (90 ft 6 in) in length was caught in the Southern Ocean on 20 March 1947.

Longest: A female blue whale landed in 1909 at the whaling station in Grytviken in South Georgia in the South Atlantic was documented as measuring "107 fot". Based on the Norwegian fot (or "fod") being equivalent to 313.74 mm (as of 1824), this gives a length of 33.57 m (110 ft 1.6 in).

Newborn calves are 6–8m (20–26 ft) long and weigh up to 3 tonnes (6,610 lb). The barely visible ovum of the female blue-whale weighing a fraction of a milligram grows to a weight of c. 26 tonnes (57,320 lb) in 22.75 months, made up of 10.75 months' gestation and the first 12 months of life. This is equivalent to an increase of 3x10¹º.

The blue whale is not the longest animal on Earth: that is the bootlace worm (Lineus longissimus), which can reach up to 55 m (180 ft) long.

The largest marine animal ever killed by hand harpoon was a blue whale killed at Twofold Bay, New South Wales, Australia, in 1910 that was 29.57 m (97 ft) long.