Toothed whale brain size with the expected brain size based on such allometric analysis provides an encephalisation quotient that can be used as another indication of animal intelligence. Sperm whales have the largest brain mass of any animal on earth, averaging and in mature males, in comparison to the average human brain which averages in mature males. The brain to body mass ratio in some odontocetes, such as belugas and narwhals, is second only to humans. Dolphins are known to engage in complex play behaviour, which includes such things as producing stable underwater toroidal air-core vortex rings or "bubble rings". Two main
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 .