Inbreeding threatens survival of 2010's namesake creature
AS Chinese people are embracing the arrival of the Year of the Tiger tonight, zoologists are worried about the survival of South China tigers.
They say the endangered species is facing a serious problem of inbreeding.
The number of captive South China tigers rose to 92 in 2009 from 60 in 2007, but all the tigers were the offspring of six wild South China tigers that were caught more than 40 years ago, said Deng Xuejian, a professor with the Department of Biology of Hunan Normal University in southern China.
"The inbreeding may lead to genetic freaks, low survival rates and poor physical makeup," Deng said.
All the genes have come from two male and four female tigers, which has led to highly identical genes in the offspring, Deng said.
"The situation may reduce the genetic diversity and cause degradation or even the extinction of the species," he said.
The tigers will lose genetic diversity if their genes are too similar, said Ma Zaiyu, president of the veterinary hospital of Changsha Zoo.
"The number of the members of a species should be at least 1,000 to maintain the stability of the species," Ma said.
In the 1990s, zoologists said the number of wild South China tigers could be less than 30. The remaining wild tigers are presumed to live in remote areas of Guangdong, Hunan, Fujian and Jiangxi provinces, Deng said.
By his analysis, Deng estimates the number of wild South China tigers could be less than 10.
No traces of wild South China tigers were reported in Hunan in the last two years, said Zhou Shuhuai, director of wildlife protection section of the Hunan provincial forestry bureau.
"The number is limited and the South China tigers scatter in different areas, which make it difficult for natural breeding between wild tigers," said Huang Gongqing, a tiger expert at the South China Tiger Breeding Base in Suzhou, a city in east China's Jiangsu Province.
"The extinction of the wild tigers will happen sooner or later," Huang warned.
Some experts have said there may be already no wild South China tigers. "However, we cannot know, as the animal is very difficult to trace," Deng said.
To avoid extinction of the species, Ma said more captive tigers should be bred and some genes might be recovered when the population reaches 1,000.
Deng suggested continuous searching for wild tigers to enrich the captive tigers' genes.
The situation is much better for the Siberian tigers in northeast China, because the number of the wild tigers is stable, experts said.
The number hovers around 20 in China, with 10 to 14 in Heilongjiang Province and eight to 10 in Jilin Province, said Sun Haiyi, deputy director of Heilongjiang Wildlife Institute
"But no more young tigers under 1 year old have been discovered in the past two years. The reason might be the number of female tigers is less than the males and the animals are relatively isolated by the mountains," Sun said.
They say the endangered species is facing a serious problem of inbreeding.
The number of captive South China tigers rose to 92 in 2009 from 60 in 2007, but all the tigers were the offspring of six wild South China tigers that were caught more than 40 years ago, said Deng Xuejian, a professor with the Department of Biology of Hunan Normal University in southern China.
"The inbreeding may lead to genetic freaks, low survival rates and poor physical makeup," Deng said.
All the genes have come from two male and four female tigers, which has led to highly identical genes in the offspring, Deng said.
"The situation may reduce the genetic diversity and cause degradation or even the extinction of the species," he said.
The tigers will lose genetic diversity if their genes are too similar, said Ma Zaiyu, president of the veterinary hospital of Changsha Zoo.
"The number of the members of a species should be at least 1,000 to maintain the stability of the species," Ma said.
In the 1990s, zoologists said the number of wild South China tigers could be less than 30. The remaining wild tigers are presumed to live in remote areas of Guangdong, Hunan, Fujian and Jiangxi provinces, Deng said.
By his analysis, Deng estimates the number of wild South China tigers could be less than 10.
No traces of wild South China tigers were reported in Hunan in the last two years, said Zhou Shuhuai, director of wildlife protection section of the Hunan provincial forestry bureau.
"The number is limited and the South China tigers scatter in different areas, which make it difficult for natural breeding between wild tigers," said Huang Gongqing, a tiger expert at the South China Tiger Breeding Base in Suzhou, a city in east China's Jiangsu Province.
"The extinction of the wild tigers will happen sooner or later," Huang warned.
Some experts have said there may be already no wild South China tigers. "However, we cannot know, as the animal is very difficult to trace," Deng said.
To avoid extinction of the species, Ma said more captive tigers should be bred and some genes might be recovered when the population reaches 1,000.
Deng suggested continuous searching for wild tigers to enrich the captive tigers' genes.
The situation is much better for the Siberian tigers in northeast China, because the number of the wild tigers is stable, experts said.
The number hovers around 20 in China, with 10 to 14 in Heilongjiang Province and eight to 10 in Jilin Province, said Sun Haiyi, deputy director of Heilongjiang Wildlife Institute
"But no more young tigers under 1 year old have been discovered in the past two years. The reason might be the number of female tigers is less than the males and the animals are relatively isolated by the mountains," Sun said.
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