A rare Barbary sheep gave birth to a pair of twin lambs last month at a zoo in north China\'s Shanxi Province. The six-year-old ewe and her one-month-old lambs were presented to the public at the zoo in the provincial capital of Taiyuan on Tuesday. The ewe delivered the female twins on Nov. 8 after an almost five-month-long pregnancy, said Shi Weixing, a breeder. The lambs, each weighing 2.5 kg, were able to stand after taking milk from their mother for the first time shortly after being born, said Shi. Barbary sheep have an average lifespan of 20 to 24 years. The breed becomes sexually mature at around three years old, and usually gives birth to one lamb at a time. \"Twins are very rare,\" he said. The lambs are in good health, and they have put on a lot of weight since they were born, he said. Apart from daily feedstuff, the zooalso prepares boiled black beans and millet for the ewe so she can provide enough milk for the twins. The Barbary sheep is the only species of wild sheep in Africa. It lives in mountainous areas at altitudes between 2,500 to 4,000 meters, and it has strong senses of sight, hearing and smell. Because of ecological damage to its habitat, the number of pure-blood Barbary sheep is less than 1,000. The species is included in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora, which means the species is not necessarily threatened with extinction but may become so if not better protected.