The largest living species of mammal is the blue whale, known scientifically as Balaenoptera musculus. Blue whales can reach lengths of up to 100 feet (30 meters) and weigh as much as 200 tons or more, making them not only the largest mammals but also the largest animals to have ever existed on Earth. Despite their colossal size, blue whales primarily feed on tiny shrimp-like animals called krill, consuming up to 4 tons of krill daily during feeding seasons. Blue whales are found in oceans worldwide and are known for their powerful song, which can be heard over long distances underwater.