The baiji (Lipotes vexillifer) is a species of river dolphin that lived in the Yangtze River system in China. It is believed to be the first dolphin species to go extinct because of human actions. The International Union for Conservation of Nature (IUCN) lists the baiji as "critically endangered: possibly extinct." Scientists have not seen it for more than 20 years, and many searches of the Yangtze River have not found any evidence of its existence. The species is also called the Chinese river dolphin, Yangtze river dolphin, Yangtze dolphin, and whitefin dolphin. The genus name "Lipotes" means "left behind," and the species name "vexillifer" means "flag bearer." It was called the "Goddess of the Yangtze" and was considered a protector by local fishermen and boatmen. It should not be confused with the Chinese white dolphin (Sousa chinensis) or the finless porpoise (Neophocaena phocaenoides). The baiji is the only species in the genus Lipotes.
The baiji population dropped sharply as China developed and used the Yangtze River for fishing, transportation, and hydroelectric power. Surveys in the 1980s suggested the baiji was the first dolphin species to go extinct because of humans. In 2001, the Chinese government approved a plan to protect the species. Conservation efforts were made, but a 2006 search found no baiji. Scientists declared the species functionally extinct. The baiji is the first recorded extinction of a large aquatic vertebrate in over 50 years, following the loss of the Japanese sea lion and the Caribbean monk seal in the 1950s. Its extinction also marked the disappearance of an entire family of river dolphins (Lipotidae). The baiji is the first well-studied cetacean species to go extinct because of human actions. Its extinction is linked to the damage to the Yangtze River, along with the loss of the Chinese paddlefish and the now extinct Dabry's sturgeon.
In 2006, Swiss economist August Pfluger, who led the baiji.org Foundation, funded a search for the dolphin. An international team, including scientists from the National Oceanic and Atmospheric Administration and Japan's Fisheries Research Agency, searched the river for six weeks. This search happened nearly 10 years after a 1997 expedition that found only 13 baiji.
In August 2007, a man in China reportedly recorded a large white animal swimming in the Yangtze River. The animal was tentatively identified as a baiji, but the presence of only one or a few individuals, especially older ones, is not enough to save a species that is functionally extinct. The last known living baiji, named Qi Qi, died in 2002. The World Wildlife Fund urges the protection of any possible baiji habitat in case the species is found and can be saved.
Anatomy and morphology
Baiji dolphins were believed to give birth between February and April, with about 30% of females becoming pregnant during this time. Pregnancy lasted 10 to 11 months, and each birth resulted in one calf. A new calf was born every two years. Newborn calves were about 80 to 90 centimeters (31 to 35 inches) long and were nursed for 8 to 20 months. Males reached sexual maturity at age four, while females reached it at age six. Adult males were approximately 2.3 meters (7 feet 7 inches) long, and females were about 2.5 meters (8 feet 2 inches) long. The largest recorded Baiji was 2.7 meters (8 feet 10 inches) long. These dolphins weighed between 135 and 230 kilograms (298 to 507 pounds) and lived about 24 years in the wild.
Baiji dolphins had a pale blue to grey back and a white belly. They had a long, slightly curved beak with 31 to 36 pointed teeth on each side of their mouth. Their dorsal fin was small and triangular, resembling a light-colored flag when they swam near the surface of the muddy Yangtze River, which is why they were called "white-flag" dolphins. Their eyes were smaller than those of oceanic dolphins.
When fleeing from danger, Baiji dolphins could swim as fast as 60 kilometers per hour (37 miles per hour), but they usually swam at speeds between 30 and 40 kilometers per hour (19 to 25 miles per hour). Because they had poor eyesight, they relied mostly on sonar to navigate. Their sonar system also helped them communicate, avoid predators, work together in groups, and express emotions. The shape of their skull and melon focused their sound emissions. Their echolocation clicks had peak frequencies between 70 kHz and 100 kHz.
Distribution
The baiji once lived in 1,700 kilometers (1,100 miles) of the middle and lower parts of the Yangtze River, from Yichang in the west to the river's mouth near Shanghai. They also lived in Poyang and Dongting Lakes and the smaller Qiantang River to the south. Over time, their range shortened by hundreds of kilometers both up and down the river, and they became limited to the main channel of the Yangtze, especially the middle section between the two large lakes, Dongting and Poyang. About 12% of the world's people live and work in the area where the Yangtze River flows, which affects the river.
Evolutionary history
The baiji is not closely related to any living dolphin species. It separated from the ancestors of the La Plata dolphin and Amazon river dolphin during the Miocene period, about 16 million years ago. The closest known relative of the baiji is Parapontoporia, which lived along the western coast of North America during the Latest Miocene and Pliocene periods. The baiji was one of five dolphin species that lived exclusively in freshwater. The other four species, including the boto and La Plata dolphin, still live in rivers such as the Río de la Plata, Amazon, Ganges, and Indus.
River dolphins are not a natural group. Studies of their mitochondrial DNA show that they split into two separate lineages: one called Platanista and another that includes Lipotes, Inia, and Pontoporia. These two groups are not closely related to each other. The Platanista lineage is part of the odontocete group, not the Mysticeti group. The Platanista lineage is older, suggesting it separated from other dolphins long ago. The Lipotes is closely related to Inia and Pontoporia, and together they form a group connected to the Delphinoidea. These findings show that the traditional group of river dolphins is not a single family. The nonplatanistoid river dolphins form a group of their own, with Lipotidae being closely related to Iniidae and Pontoporiidae. These results match earlier studies using genetic markers.
The baiji in the Yangtze River has low genetic diversity. Scientists used a method called AMOVA to study genetic differences and found that the baiji population is highly structured. Males showed greater genetic differences than females, suggesting that females move more frequently between groups.
The adaptations of the baiji and other whales to life in water happened slowly and involve changes in specific genes. Studies of the baiji’s genome show that it has a slow rate of genetic change and adaptations to its aquatic environment. Scientists believe that a population decline occurred near the end of the last ice age, a time when temperatures dropped rapidly and sea levels rose. Research also found genes in the baiji’s genome that help repair DNA damage, which are not found in other mammals. These genes are linked to brain development and conditions like microcephaly. The slower rate of genetic changes in whales may be connected to improvements in DNA repair systems. Over time, river dolphins, including the baiji, have developed smaller eyes and less acute vision, likely due to poor visibility in rivers and estuaries. Scientists discovered four genes in the baiji that no longer function due to genetic changes. The baiji has the lowest rate of genetic variation among mammals, which may be due to its slow molecular evolution. However, the drop in genetic diversity is likely caused by the sharp decline in the baiji population in recent decades and the limited breeding that followed.
Studies of the baiji’s population history over the last 100,000 years show a steady decrease in numbers during the last ice age, a severe population drop during the last ice age’s end, and a later increase in numbers as sea levels reached their current levels. The connection between population changes, temperature, and sea levels suggests that climate changes played a major role in shaping the baiji’s population history.
Folklore
According to Chinese folklore, a young girl lived with her stepfather near the Yangtze River. Her stepfather was mean and greedy, only thinking about himself. One day, he took the girl on a boat and planned to sell her at a market. On the river, he became attracted to her beauty and tried to harm her. She jumped into the river to escape. A storm hit, and the boat sank. After the storm passed, people saw a dolphin swimming in the river. This dolphin was believed to be the girl’s spirit, known as the "Goddess of the Yangtze." The baiji, a type of dolphin found in the Yangtze River, is seen as a symbol of peace and prosperity.
In popular culture
The baiji, a type of river dolphin, has appeared in movies, books, and other media because it is considered a valuable symbol of China and is very endangered. Stamps and coins have shown pictures of the Yangtze river dolphin. Before the Minecon Earth 2018 event, a poll asked Chinese players to guess which important Chinese animal would be added to the video game Minecraft. In 2024, the Hangzhou Super Cup, a canoeing competition in China, used a baiji named "豚豚" (tún tún) as its mascot.
Conservation
In the 1950s, there were about 6,000 baiji dolphins. However, their numbers dropped quickly over the next 50 years. By 1970, only a few hundred remained. By the 1980s, their number had fallen to 400, and by 1997, only 13 were found during a full search. The last confirmed sighting of a baiji was in August 2004. Since then, there have been reports of possible sightings, but none have been confirmed. The U.S. government lists the baiji as an endangered species under the Endangered Species Act. Scientists now believe the baiji is functionally extinct, meaning it no longer reproduces in the wild.
The World Conservation Union (IUCN) lists several threats to the baiji. These include hunting during the Great Leap Forward, getting tangled in fishing nets, using electric fishing, colliding with boats, losing habitat, and pollution. Other threats include a lack of knowledge about the baiji’s history and ecology, the environmental effects of the Three Gorges Dam, and failure to protect the species.
During the Great Leap Forward, people stopped respecting the baiji, and it was hunted for its meat and skin. This caused the population to drop quickly.
As China’s economy grew, pressure on the Yangtze River dolphin increased. Industrial and household waste entered the river. The riverbed was dug up and covered with concrete. Ship traffic increased, and fishermen used larger, more dangerous nets. Noise pollution made the nearly blind dolphin collide with boat propellers. Fish that the baiji relied on for food declined sharply in the late 20th century, with some species dropping to one-thousandth of their original numbers.
Human activities, such as boat collisions and dam construction, also harm other freshwater dolphins. However, the main cause of the baiji’s decline was likely uncontrolled fishing. Fishermen used rolling hooks, nets, and electric fishing, which caused many baiji deaths. In the 1970s and 1980s, about half of all known baiji deaths were from fishing gear. In the 1990s, 40% of recorded deaths were from electric fishing. Unlike other large animals that went extinct due to direct harm, the baiji died from indirect effects of human activity, such as overfishing.
The baiji’s extinction shows the worsening health of the Yangtze River. In the 1970s and 1980s, about half of all baiji deaths were from fishing nets. By the early 2000s, electric fishing became the most immediate threat to the species. Though banned, this practice is still used illegally in China. The Three Gorges Dam reduced the baiji’s habitat and increased ship traffic, making survival harder.
Some scientists believe pollution caused diseases in the baiji population, such as infections from parasites. The baiji’s dependence on the Yangtze River may have exposed it to diseases from both land and sea. Studies have not yet confirmed this, but scientists think the river’s water might have higher levels of harmful pathogens than the ocean. These pathogens could cause large disease outbreaks, which have killed thousands of marine mammals in recent years. Some baiji had parasites in their stomachs, suggesting parasitic infections may have contributed to their decline.
Scientists note that the baiji’s shrinking range is not directly linked to its population loss. Research shows the baiji moves long distances over years, so reduced geographic range did not cause its decline.
In the 1970s, China recognized the baiji’s decline and banned killing it, limited fishing, and created nature reserves. In 1978, the Chinese Academy of Sciences formed the Freshwater Dolphin Research Centre. In the 1980s and 1990s, attempts were made to capture baiji and move them to a reserve. A breeding program was planned to help the species recover, but capturing the dolphins was difficult, and few survived in captivity.
In 1996, the Baiji Dolphin Conservation Foundation of Wuhan was created. It raised about 1 million yuan (about $100,000) to preserve baiji cells and maintain facilities, including the Shishou Sanctuary, which was flooded in 1998.
Since 1992, five protected areas along the Yangtze River have been set aside for baiji. Four are in the main river, where fishing is banned and baiji are protected: two national reserves (Shishou City and Xin-Luo) and two provincial (Tongling and Zhenjiang). Five nature reserves have been created along the river. While banning harmful fishing in these areas might slow the baiji’s decline, conservation efforts have not stopped the population from falling. As humans use the river’s resources, it remains unclear if the baiji can return to the wild.
In Shishou and Tongling, two semi-natural reserves were built to help the baiji and the Yangtze finless porpoise breed. Careful management allowed both species to survive and reproduce, offering hope for the baiji’s recovery.
The fifth reserve is an oxbow lake near Shishou, called the Tian-e-Zhou Oxbow Semi-natural Reserve. Together, the five reserves cover about 350 kilometers, or one-third of the baiji’s original habitat. Two-thirds of their habitat remains unprotected.
In addition to the reserves, five “Protection Stations” have been set up in Jianli, Chenglingji, Hukou, Wuhu, and Zhengjiang. Each station has two observers and a boat to patrol, monitor, and investigate illegal fishing.
In 2001, the Chinese government approved a Conservation Action Plan for Yangtze River dolphins. This plan focused on the same three measures discussed in a 1986 meeting and became national policy for protecting the species.