The last documented sighting of China's baiji dolphin, or Yantze River dolphin, was in 2002, and while the species is listed as critically endangered, scientists say it may already be extinct. In 2006, scientists from the Baiji Foundation traveled up the Yangtze River for more than 2,000 miles equipped with optical instruments and underwater microphones, but were unable to detect any surviving dolphins. The foundation published a report on the expedition and declared the animal functionally extinct, meaning too few potential breeding pairs remained to ensure the species' survival.
The decline in the baiji dolphin population is attributed to a variety of factors including overfishing, boat traffic, habitat loss, pollution and poaching. Deemed "the goddess of the river," the dolphin's skin was highly valuable and used to make gloves and handbags.