Zoo officials in Washington hope they can get lucky again with female giant panda Mei Xiang.

美国华盛顿动物园管理人员希望能让大熊猫“美香”再度怀孕产崽。

The Smithsonian's National Zoo is trying to get the 18-year-old giant panda pregnant in hopes she will deliver her fourth living cub in a move to boost the species, officials said on Friday.

美国史密森尼国家动物园上周五5月26日表示，园方希望让18岁的大熊猫“美香”再度怀孕生下第四胎熊猫宝宝，以增加大熊猫物种的数量。

There are about 1,800 giant pandas in the wild, according to the International Union for Conservation of Nature, which classifies them as "vulnerable."

目前世界仅存野生大熊猫1800只，国际自然保护联盟已将其列为“易危”物种。

Mei Xiang had artificial insemination performed on her twice on Thursday after she had shown signs of being in estrus, or capable of becoming pregnant, the zoo said in a statement.

园方在声明中说，自从“美香”有发情迹象或可怀孕迹象后，园方在5月25日周四时对其采取了两次人工授精。

The pregnancy window is very narrow for pandas, which are native to China and star attractions at the National Zoo. Estrus lasts only 24 to 72 hours per year, and Mei Xiang's estrogen levels had peaked on Wednesday, it said.

大熊猫栖息于中国，自来到美国国家公园后备受游客瞩目。大熊猫的生殖期很短，每年发情时间只有24到72小时，“美香”的雌性激素在周三时达到了最高水平。

If Mei Xiang becomes pregnant, the cub likely would be born around the end of September, the zoo said. It turned to artificial insemination using semen from the zoo's 19-year-old male, Tian Tian, when he and Mei Xiang were unable to mate.

动物园表示，如果“美香”怀孕，则有望于今年9月底产下幼崽。采用人工授精的方法是因为没有办法使19岁雄性熊猫“添添”和“美香”交配，所有仅使用了添添的精子。

Giant pandas have low reproductive rates and Mei Xiang has had several false pregnancies. She has three surviving cubs - Tai Shan, born in 2005; Bao Bao, born in 2013, and Bei Bei, born in 2015 and still at the zoo.

大熊猫的生殖率很低，“美香”多次出现假孕的情况。她曾先后成功产下三只熊猫幼崽——2005年的“泰山”、2013年的“宝宝”，还有2015年的“贝贝”，“贝贝”目前仍在该动物园中。

（翻译：红楼里的小石头）