Blue whale is a marine mammal, and they are the largest animal ever existed. They're 30 meters in length and weight of about 180 tons they （ weighting them for the size that it is very difficult, and they are usually weighted by parts has been ）. There are 3 species of blue whales, their diet consists on krill (small crustaceans). When whaling is regulated by the international community in recent blue whale during the XX century large whaling for the until 1966, in serious danger of extinction on the verge has.