Which river dolphin is considered functionally extinct?

The baiji, or Yangtze river dolphin, is the river dolphin considered functionally extinct. Its scientific name is Lipotes vexillifer, and it was native to China’s Yangtze River system. The species has not been definitively observed in many years, and extensive surveys have failed to find a surviving, self-sustaining population.

The baiji’s decline accelerated as the Yangtze became increasingly industrialized. Heavy boat traffic, fishing gear, pollution, habitat disruption, and collisions placed pressure on a dolphin that depended on a complex freshwater ecosystem. In 2006, an international survey failed to locate any baiji, leading researchers to describe it as functionally extinct.

“Functionally extinct” means that so few individuals may remain that the species can no longer reliably reproduce or maintain a viable population. It is not always identical to absolute extinction: an isolated animal might theoretically survive, and occasional unconfirmed sightings have continued.

The last confirmed baiji in captivity, a male named Qi Qi, died in 2002. The baiji is often called the Chinese river dolphin or Whitefin dolphin and is distinct from the finless porpoise and the Chinese white dolphin.