Editing Cetacean intelligence (section)

===Complex play===
Dolphins are known to engage in complex play behavior, which includes such things as producing stable underwater [[toroid]]al air-core [[vortex]] rings or "[[bubble ring]]s".<ref>{{Cite web |title=The physics of bubble rings and other diver's exhausts |url=http://www.deepocean.net/deepocean/index.php?science09.php |url-status=dead |archive-url=https://web.archive.org/web/20061006163548/http://www.deepocean.net/deepocean/index.php?science09.php |archive-date=2006-10-06 |access-date=2006-10-24}}</ref> There are two main methods of bubble ring production: rapid puffing of a burst of air into the water and allowing it to rise to the surface, forming a ring; or swimming repeatedly in a circle and then stopping to inject air into the [[Helix|helical]] vortex currents thus formed. The dolphin will often then examine its creation visually and with sonar. They also appear to enjoy biting the vortex-rings they have created, so that they burst into many separate normal bubbles and then rise quickly to the surface.<ref>{{Cite web |title=Bubble rings: Videos and Stills |url=http://www.bubblerings.com/bubblerings/media.cfm |url-status=dead |archive-url=https://web.archive.org/web/20061011195647/http://www.bubblerings.com/bubblerings/media.cfm |archive-date=2006-10-11 |access-date=2006-10-24}}</ref> Certain whales are also known to produce bubble rings or bubble nets for the purpose of foraging. Many dolphin species also play by riding in waves, whether natural waves near the shoreline in a method akin to human "body-surfing", or within the waves induced by the bow of a moving boat in a behavior known as ''bow riding''.