Two researches done in 1970s and 1980s showed that there were some 1000 wild pandas in about 37 counties of China, in a habitat of around 13,000 square kilometers. Another survey by the State Bureau of Forestry of China in 2006 got a result that the amount of wild pandas in China increased to 1596, with 161 being reared in pens. As the rarest breed of ursidae, giant pandas have been listed as one of the endangered animals in the world. With the scientific name "猫熊(mao xiong)" in Chinese, giant pandas are commonly called "熊猫(xiong mao)" in mainland China as a matter of fact, which is a reversed pronunciation of their scientific name. So why the "inaccurate" name "熊猫"? The reason for that can be traced back to the first half of 1900s when reading from right to left was still the customary way in China: On one occasion, the former Chongqing Beibei Museum exhibited some specimens of giant panda with the name "猫熊" which should be read from left to right, but journalists used the name in a reversed way according to the reading way at that time, hence, "熊猫" was widely known to the public and passed down to this day. With particularly favorable natural conditions, Chengdu of Sichuan Province has been being home of pandas. Chengdu Research base of Giant Panda Breeding, which is equipped with world-class facilities for pandas, is so far the biggest and most renowned panda base with most pandas among all the zoos and parks China as well as the most popular choice for tourists to visit pandas in the world. With "Ailuaractos lufengensis" being their forefather, giant panda is a kind of ancient animal living in the same age with saber-toothed tigers and some other prehistoric lives which have been extinct and fossilized, thus pandas are called "living fossil" by zoologists. Mainly living in the north of Sichuan Province, Shaanxi Province and the south of Gansu Province, pandas are put under national production in China. With bamboo as their favorite food, pandas feed on almost all kinds of the bamboos that can be found in mountain regions (occasionally eat meat such as bamboo rats or bodies of other animals). Their unique dietary habit brings them another name – bamboo bear (by the local people). Normally, pandas live in places wher there are two kinds of bamboos at least, the reason for that is that they can eat other bamboos if one kind of the bamboos blooms (bamboo will wither after blooming, which happen every 30-120 years for one cluster of bamboo). If all the bamboos bloom at a same time, pandas will face the threat of starvation. In the open, pandas spend as many as 14 hours in eating and the rest of a day is the time for sleep and short-distant moves. An adult panda eat 12-38 kg of food every day, which accounts for nearly 40% of its weight. Although born with weak sense of hearing and eyesight, pandas live in dense forests in deep mountains with sensitive smell and special skills of climbing tree and swimming.