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Tigers earning their wild stripes
Trainers looking after Cathay and Hope had every reason to celebrate when the two young South China tigers made their first kill in late July in their new home in South Africa. Their first victim, a baby bushbuck, hung lifeless after the cubs had used their powerful canines to break its neck. Hope came back the next day to play with the remains of the carcass. "Whichever one actually killed the small antelope doesn't matter - this was a great achievement for Cathay and Hope," a diary of their progress reads. Cathay and Hope are the first two young pioneering South China tigers to receive training abroad for getting back to the wild. Their "studies abroad" are the first stage of an extensive plan China has adopted to conserve the animals with a view to trying to recover a wild population. Endangered Throughout China's long history, tigers have been a symbolic indigenous species of the country's culture. Yet today, this South China species is possibly the most endangered of the five remaining tiger subspecies. In one Sino-American field survey carried out during 2001 and 2002, Ronald Tilson, from the Minnesota Zoo of the United States, and his colleagues trekked the hills and mountains in eight nature reserves in Fujian, Zhejiang, Hunan, and Jiangsu provinces. These reserves were identified by the State Forestry Administration as the natural habitats most likely to be home to tigers. The researchers installed camera-traps, along footpaths and animal trails, to photograph the animals. But they failed to snap even small creatures that would be a tiger's natural prey, let alone the big cats themselves. "After continuous searches in these areas and interviewing the local villagers, we found no trace of the wild South China tiger," Tilson told the 19th International Zoological Congress held in Beijing last week. Local villagers told the researchers there had been no report of livestock depreciation because of tigers in the last decade. From this, Tilson could only deduce that there were in fact no indigenous tigers living in their ancestral home. The researchers found out that forest areas earmarked as tiger reserves, averaging about 100 square kilometres in size, were too small to support even a few tigers in the wild. Commercial tree farms and other habitat conversion is common, and people and their livestock dominate these fragments. As these searches have turned out to be almost fruitless, conservationists have had to turn to the small number of tigers in zoos across China. At the moment, there are 78 South China tigers - 43 males and 35 females - living in captivity in 19 zoos or wildlife parks around the country. They are primarily the descendants of 18 wild tigers captured in the late 1950s, which comprised six females and 12 males. Only two females and four males successfully reproduced. Xie Zhong, a research fellow with the Chinese Association of Zoological Gardens, said the main problem with this was the loss of genetic diversity, because all the individuals in captivity were the offspring of six animals. The average inbreeding rate among tigers is 0.285. Astonishingly, the inbreeding coefficient of seven South China tigers detected by Xie's team has already reached 0.492, indicating a severe lack of genetic diversity in their reproduction. In the 1980s, when the captive population was still in its first or second generation, genetic diversity was still fairly high. "But the very small number of founding parents has led to a steady increase in the inbreeding rate, which subsequently affects the breeding capability of the group," said Xie. "We have witnessed a vicious circle in the past years. Reduced fertility results in a low population. Then this small population again perpetuates more inbreeding." Xie said she and her colleagues were not sure how to deal with the dilemma. On one hand, they hoped to breed more and increase the population of the animals. But genetic variation was important and breeding between certain pairs of tigers had to be limited, she said. But because there are so few of the creatures living in the wild, it seems there are few options to mix up the breeding lines. "It is unlikely we will be able to introduce wild species," Xie said. A second option could be to apply modern biotechnology, such as cloning, but there are not enough statistics about this to give results any certainty. "Maybe one day we will have to consider hybridization with a closely related subspecies. "But that really would be the last option," said Xie. Retraining programme Despite the difficulties, China is still going ahead with its plan to try and reintroduce South China tigers to the wild. The Tiger Conservation Project was listed in 2001 as one of 15 species conservation projects under the Project Plan of National Wildlife Protection and Nature Reserve Construction issued by the State Forestry Administration. The main objectives are to increase the natural, wild population of tigers in China by restoring and protecting their natural habitat. Cathay and Hope have thus become pioneers. Since they arrived in South Africa in September 2003, they have been learning some basic hunting skills - stalking, jumping, running and chasing. From first observations of living prey to the first catch - a wild partridge - it took the two cubs nearly 90 days. "However, later on, we witnessed a rapid improvement in their hunting skills," Lu Jun, office director of the National Wildlife Research and Development Centre with the State Forestry Administration of China, said during the International Zoological Congress. It was the 48th week in their new home when the pair made their first kill of a larger animal. "The tigers have proved that their hunting ability has matured from killing easy prey, to killing more challenging game birds, then antelope. On top of that, they are now learning that prey is not only there to be caught but to be consumed," the diary adds. Lu said it was only a matter of time before the pair started hunting larger prey, using natural shelter to hide while stalking. Cathay and Hope will be moved to larger areas where they will have more prey to hunt. Meanwhile, Lu said that China is ready to send a few more young cubs to join Cathay and Hope for training in the wild. But the next real step is an experimental area in their actual homeland, China. "We are trying to restore them to habitats suitable for their survival in the wild," said Lu. At the moment, two sites have been selected as recovery sites in the original home range of the tigers - in Jiangxi and Hunan provinces. Each covers an area of more than 150 square kilometres. The proposed areas have hilly landscapes and are already home to more than 180 species of animal, including muntjac, wild boar and some species of leopard - all potential prey for tigers. Lu said depending on the progress of the first two steps, conservation workers would take the next move, returning the tigers to the experimental areas to try and re-establish the wild population. Many zoologists believe the tiger conservation programme in China should go far beyond rescuing South China tigers, or any specific subspecies. It should generate high awareness for nature conservation in general.
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