大熊猫的祖先是始熊猫（Ailuaractos lufengensis），这是一种由拟熊类演变而成的以食肉为主的最早的熊猫。始熊猫的主枝则在中国的中部和南部继续演化，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 and over 180 were reported to live in captivity by August 2006 in mainland China (another source by the end of 2006 put the figure for China at 221), with twenty pandas living outside of China. However, reports show that the numbers of wild panda are on the rise.
The giant panda has long been a favorite of the public, at least partly on account of the fact that the species has an appealing baby-like cuteness that makes it seem to resemble a living teddy bear. The fact that it is usually depicted reclining peacefully eating bamboo, as opposed to hunting, also adds to its image of innocence. Though the giant panda is often assumed docile because of their cuteness, they have been known to attack humans, usually assumed to be out of irritation rather than predatory behavior.
The Giant Panda has a very distinctive black-and-white coat. Adults measure around 1.5 m long and around 75 cm tall at the shoulder. Males can weigh up to 115 kg (253 pounds). Females are generally smaller than males, and can occasionally weigh up to 100 kg (220 pounds). Giant Pandas live in mountainous regions, such as Sichuan, Gansu, Shaanxi, and Tibet. While the Chinese dragon has been historically a national emblem for China, since the latter half of the 20th century the Giant Panda has also become an informal national emblem for China. Its image appears on a large number of modern Chinese commemorative silver, gold, and platinum coins.
The Giant Panda has an unusual paw, with a "thumb" and five fingers; the "thumb" is actually a modified sesamoid bone, which helps the panda to hold the bamboo while eating. Stephen Jay Gould wrote an essay about this, then used the title The Panda's Thumb for a book of essays concerned with evolution and intelligent design. The Giant Panda has a short tail, approximately 15 cm long. Giant Pandas can usually live to be 20-30 years old while living in captivity.
Until recently, scientists thought giant pandas spent most of their lives alone, with males and females meeting only during the breeding season. Recent studies paint a different picture, in which small groups of pandas share a large territory and sometimes meet outside the breeding season.
Like most subtropical mammals, but unlike most bears, the giant panda does not hibernate.
Pandas eating bamboo at the National Zoo in Washington, D.C.Despite its taxonomic classification as a carnivore, the panda has a diet that is primarily herbivorous, which consists almost exclusively of bamboo. This is an evolutionarily recent adaptation. Pandas lack the proper enzymes to digest bamboo efficiently, and thus derive little energy and little protein from it.
While primarily herbivorous, the panda still retains decidedly ursine teeth, and will eat meat, fish, and eggs when available. In captivity, zoos typically maintain the pandas' bamboo diet, though some will provide specially formulated biscuits or other dietary supplements.如果觉得关于熊猫的英语文章2300字不错，可以推荐给好友哦。