The distributions of the five subspecies of blue whale are outlined below. The origin of the name "Blue Whale" is uncertain. She is known for her Blue Whale Project. Krill are also the main prey of baleen whales, including the blue whale. Kaalidas suspects that the deceased women could be victims of the Blue Whale Challenge. It is now thought to be the same subspecies as the pygmy blue whale. Blue whale calls last between ten and thirty seconds. It is perhaps more closely related to its larger relative, the blue whale. Police reports claim that Nearonov's involvement in the Blue Whale game was his "hobby". It is the second-largest species on Earth after the blue whale. The blue whale is the largest known animal. The blue whale is the largest mammal. The first news about Blue Whale appeared in Bulgaria in mid-February 2017. There are at least nine separate blue whale acoustic populations worldwide. It featured a blue whale, the first full-cast of a blue whale ever created.