In 2006, and again in 2012, marine researchers reluctantly declared the Chinese River Dolphin, also known as the Baiji, to be “functionally extinct” after extensive surveys of the Chinese waterway showed no signs of the animal.
Both the U.S. Fish and Wildlife Service and the International Union for Conservation of Nature (IUCN) list the baiji as endangered, not extinct. For an animal to be added to the IUCN’s comprehensive extinction list there must be, “no reasonable doubt that the last individual has died.” Furthermore, final closure requires that “exhaustive” surveys in an animal’s known habitat have failed. Though some organizations have been reluctant to declare the official extinction of the baiji, researchers who have studied the Yangtze River have concluded that between polluted conditions in the congested river, no anecdotal evidence of sightings, and no physical evidence of the animal’s existence that the baiji is “likely to be extinct.”