Whale 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. Small whales are known to engage in complex play behaviour, which includes such things as producing stable underwater toroidal air-core vortex rings or "bubble rings". There are two main methods of bubble ring production: rapid puffing of a burst of air into the water
Fin whale Fin whale The fin whale ("Balaenoptera physalus"), also known as finback whale or common rorqual and formerly known as herring whale or razorback whale, is a marine mammal belonging to the parvorder of baleen whales. It is the second-largest species on Earth after the blue whale. The largest reportedly grow to long with a maximum confirmed length of , a maximum recorded weight of nearly , and a maximum estimated weight of around . American naturalist Roy Chapman Andrews called the fin whale "the greyhound of the sea ... for its beautiful, slender body is built like a racing yacht