Baiji

The baiji (Lipotes vexillifer) was a freshwater dolphin endemic to the Yangtze River in China, the sole member of the family Lipotidae and a lineage that had diverged from other river dolphins some sixteen to twenty million years earlier. Pale grey above and white below, with very poor eyesight and a long, slightly upturned beak, it navigated the murky river largely by echolocation. In Chinese tradition it was revered as the “Goddess of the Yangtze.”

As China industrialized, the baiji was caught between many pressures at once. It was killed by entanglement in fishing gear, especially rolling-hook longlines, and increasingly by electrofishing; it was struck by the heavy boat traffic of one of the world’s busiest rivers; and its habitat was degraded by dam construction, pollution, and dredging.

The population fell with terrible speed: from an estimated 6,000 animals in the 1950s to roughly 400 by 1980, and to just 13 confirmed in a survey of 1997. A six-week international survey in late 2006 covering the dolphin’s entire historical range in the main Yangtze channel found not a single baiji.

On the basis of that survey the species was declared functionally extinct in a 2007 paper — the first cetacean driven to extinction by human activity in modern times, and the disappearance of an entire mammal family. A single unconfirmed sighting was reported in 2007, but no baiji has been verified since.