The blue whale is a marine mammal belonging to the baleen whales. The length of the blue whale is 98 ft and weight is 190 tonnes or more. It is the largest existing animal and the heaviest that has ever existed. The blue whale’s body can be various shades of bluish-grey dorsally and somewhat lighter underneath.
Blue whales have row of 300-400 baleen plates on each side of the mouth, which are black in color and range in length from 50 cm in front to 100 cm in back. It’s diet consists almost exclusively of small crustaceans known as krill. An adult blue whale can eat up to 40 million krill in a day. Females typically give birth once every two to three years at the start of the winter. The calf weighs about 2.5 tonnes and is around 7 metres in length. Blue whale calves drink 380–570 litres of milk a day. Scientists estimate that blue whales can live for at least 80 years.