Sperm whale . Myoglobin, which stores oxygen in muscle tissue, is much more abundant than in terrestrial animals. The blood has a high density of red blood cells, which contain oxygen-carrying haemoglobin. The oxygenated blood can be directed towards only the brain and other essential organs when oxygen levels deplete. The spermaceti organ may also play a role by adjusting buoyancy (see below). The arterial retia mirabilia are extraordinarily well-developed. The complex arterial retia mirabilia of the sperm whale are more extensive and larger than those of any other cetacean. Atop the whale's skull is positioned a large complex of organs filled
Blue whale penis dubbed "a real Moby Dick". The specimen is just the tip, as the entire organ, when intact, would have been about long and weighed about , well above average for even a blue whale. By comparison, an adult elephant's penis is the largest penis of any land animal at on average. Blue whale penis The blue whale has the largest penis in the animal kingdom. It is commonly cited as having an average penis length of to and a diameter of to . The reported average penis length varies but is usually mentioned to have an average length of .