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
Cryptid whale female individual on Orkney, saying its dorsal fins was similar to a "mizzen mast", and the whale, based on Sibbald’s account, was described as "P. tursio". However, naturalist Georges Cuvier disregarded Sibbald’s claim as a bad description of the carcass, as well as dismissing the name "P. tursio". Another alleged sighting was off the Annapolis Basin, Nova Scotia, Canada on September 27, 1946, where the creature was apparently trapped there for 2 days. Its length was estimated to be between . The Alula whale, or the Alula Killer, or "Orcinus mörzer-bruynsus", was discussed and illustrated for the first time, but