Baiji

Illustration

The Yangtze River dolphin ( Lipotes vexillifer ), also known as the Yangtze River dolphin or baiji (Chinese白 鱀 豚, Pinyin báijìtún ), is an indigenous to exclusively in the Yangtze River dolphin. He is regarded since the 1980s as one of the rarest mammals in the world and is probably already extinct.

The name Lipotes derives from the Greek word leipos from, which can be translated as retarded or left and refers to the very limited range of the species. Vexillifer derived from the syllables of vexillum flag fer for wear, ie for flags supporting.

Features

The Yangtze River dolphin is up to 250 inches long and up to 160 kilograms. The males are likely to remain somewhat smaller than the females, with about 220 centimeters. He is colored pale gray upper side to lower side and bluish - white. The flukes and the flippers wearing a gray upper side and lower side a white coloring. He has a small triangular dorsal fin with a blunt tip.

Its almost beak-like snout is clearly separated from the head and slightly bent the tip upwards. It is very narrow and has per jaw half between 30 and 35 similarly shaped, cone -shaped teeth. The forehead is steeply sloping and the eyes have atrophied, but not functional.

Dissemination

Originally it was believed that the Yangtze River dolphin is limited to the Dongting Lake before it was realized in the 1970s that he was found on a length of 1900 kilometers from the mouth of the Yangtze River upstream and neighboring East China's Qiantang River. About every four kilometers was a river dolphin are found. At high tide the animals penetrated in tributaries of the river and lakes. From the Dongting Lake of the whale disappeared after had accumulated in the water by the agricultural use very large amounts of sediment. After that he was seen only in the broad, slow-flowing middle section of the Yangtze River.

Way of life

Little is known about the way of life. Because of vestigial eyes Chinese river dolphins rely on echolocation during prey capture. Their food are exclusively fish they prey on only twenty seconds -long dives. The range of prey fish is very large, the main prey make this elongated catfish is that they hunt on the sea bottom.

The Yangtze River dolphin lives primarily as a loner. Previously, he was rather to be found in pairs or small groups of three to six animals, and occasionally groups were up to ten animals sighted. Most of the time keeps the river dolphin to just below the water surface. An ascent comes first the head to the fore and the animal appeared with a hump- shaped curve again. The Fluke did not show up there.

About the reproductive behavior of the Chinese river dolphin is almost nothing known. The pups came with less than 95 cm body length and 10 kg body weight on the world.

In captivity, only two animals were maintained. These were to the male animal Qiqi who was injured by a fisherman and then held from 1980 to 2002 in Wuhan Institute of Hydrobiology, as well as another animal that one year (1996 to 1997) in Shishou semi -natural Baiji Dolphin Sanctuary lived and then died. 1998 also a female, near Shanghai, has been captured, but it refused food and died a month later.

System

According to the fossil record of the Yangtze River dolphin populated about 20,000 years ago from the Pacific. He is the only member of the genus Lipotes.

The systematics of river dolphins is controversial. While previously all members of this group were considered to be convergent and not related to each other, one goes after molecular genetic studies now assume that the Amazon river dolphin and the La Plata dolphin are related to the Chinese river dolphin. Wilson & Reeder (2005) therefore classify them in a joint family, Iniidae. The also living in Asian freshwater dolphins are underway, however, not closely related with them.

Inventory and threat

The first description of the animals derived from nature encyclopedia Erya from the Han Dynasty ( 206 BC to 220 AD ). Biologists estimate that at this time were still about 5,000 river dolphins in the Yangtze River. 1978 was established for the study of animals, the freshwater dolphin research center (淡水 海豚 研究 中心) of the Chinese Academy of Sciences.

In east China's Qiantang River, the river dolphin had not been seen since the 1950s. By 1980 the stock in the Yangtze River was estimated at around 400 animals. Especially the Chinese industrialization had the stock of these animals very added. The pollution of the Yangtze River, the excessive shipping and frequent entanglement in fishing nets ( " bycatch " ) had brought the way to the edge of extinction. Many documented deaths are attributed to interference of the lines and hook fishing, were added frequent collisions with motor boats, the number of which increased massively on the Yangtze River.

Although the People's Republic of China in 1979, the dolphin recognized as an endangered species and in 1983, under the most stringent protection and a ban on hunting issued, the threatening circumstances for the animal did not change. 1986 no 300 Baijis were found in a census in 1990 the population was about 200 animals. By 1997, this number was reduced to an estimated maximum of 50; 23 animals were actually counted. 1998, there were finally only seven animals. 2001 a stranded female was found in 2002 and the last time a live animal was photographed.

In the years 2006 and 2007 several attempts were made ​​to find any live specimens of the Chinese river dolphin. However, these were unsuccessful, so the scientists involved went out of the river dolphin is final extinct. The Baiji dolphin would thus be the first extinct in historical times animals are found. However, in 2007 appeared in the press also reports that the river dolphin was still seen by locals and even filmed.