Blue whale -largest known animal ever to have existed

The blue whale  is a Marine Mammal  belonging to the Baleen Whales

At 30 metres (98 ft) in length and 170 Tonnes (190 Short Tons) or more in weight, it is the largest known animal ever to have existed

The blue whale has a long tapering body that appears stretched in comparison with the stockier build of other whales.The head is flat, U-shaped and has a prominent ridge running from the blowhole to the top of the upper lip.The front part of the mouth is thick with baleen plates; around 300 plates (each around one metre (3.2 ft) long) hang from the upper jaw, running 0.5 m (1.6 ft) back into the mouth. Between 70 and 118 grooves (called ventral pleats) run along the throat parallel to the body length. These pleats assist with evacuating water from the mouth after lunge feeding (see feeding below)

Blue whales can reach speeds of 50 kilometres per hour (31 mph) over short bursts, usually when interacting with other whales, but 20 kilometres per hour (12 mph) is a more typical traveling speed

A blue whale's Tongue weighs around 2.7 metric tons (3.0 short tons) and, when fully expanded, its mouth is large enough to hold up to 90 metric tons (99 short tons) of food and water

Blue whales feed almost exclusively on krill(small crustaceans) though they also take small numbers of copepods(a group of small crustaceans)

The name krill comes from the Norwegian word krill meaning "young fry of fish"

Females typically give birth once every two to three years at the start of the winter after a Gestation Period of 10 to 12 months

The calf weighs about 2.5 metric tons (2.8 short tons) and is around 7 metres (23 ft) in length

Scientists estimate that blue whales can live for at least 80 years.The longest recorded study of a single individual is 34 years, in the eastern North Pacific.

The whales' only natural predator is the Orca(killer whale)