演化，其中一种在距今约300万年的更新世初期出现，体形比现在的熊猫小，从牙齿推断它已进化成为兼食竹类的杂食兽，此后这一主支向亚热带扩展，分布广泛，在华北、西北、华东、西南、华南以至越南和缅甸北部都发现了化石。在这一过程中，大熊猫适应了亚热带竹林生活，体型逐渐增大，依赖竹子为生。在距今50-70万年的更新世中、晚期是大熊猫的鼎盛时期。现在的大熊猫的臼齿发达，爪子除了五趾外还有一个“拇指”。这个“拇指”其实是一节腕骨特化形成，学名叫做“桡侧籽骨”，主要起握住竹子的作用。美国生物学家史蒂芬·杰伊·古尔德(stephen jay gould)——关于这个写过一篇散文，后来又用《熊猫的拇指》作为一部散文集的名称。

　　the giant panda (ailuropoda melanoleuca) ("black-and-white cat-foot") is a mammal classified in the bear family, ursidae, native to central-western and southwestern china. it is easily recognized by its large, distinctive black patches around the eyes, ears and on its rotund body. though technically a carnivore, the panda has a diet which is 98% bamboo. however, they may eat other foods such as honey, eggs, fish, and yams.

　　the giant panda is an endangered animal; an estimated 3,000 pandas live in the wild[2][3] and over 180 were reported to live in captivity by august 2006 in mainland ch

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