Dec. 30, 2005 — A giant panda cub born at the San Diego Zoo on Aug. 2 is now big enough to go on public display for three hours a day, zoo officials said Thursday.

At 21 weeks old, the female cub is scurrying and climbing around her zoo habitat with "vigor," and even performing the occasional headstand, according to the zoo.

Su Lin, which in Chinese means "a little bit of something very cute," and her mother, Bai Yun, will be on exhibit from 9 a.m. to noon every morning, the zoo said on its Web site.

In the afternoons, Su Lin will have the choice to remain in the enclosure or retire to her den.

Su Lin was named after the first giant panda to arrive in America in 1936. The original Su Lin was originally thought to be a male, but later turned out to be a female.

In her latest health exam, the cub measured 76 centimeters (2.6 feet) tall and weighed in at seven kilograms (15.4 pounds).

She is the third giant panda cub to be born at the San Diego Zoo. The first, Hua Mei, was born in 1999 and became the first panda cub to reach maturity in the United States. She was sent to China in February 2004 and is now part of their giant panda conservation program.

The zoo's second panda cub, Mei Sheng, was born in 2003. All three cubs were born to Bai Yun, whose name means "white cloud" in Chinese.

Captive panda births remain exceedingly rare, especially outside of China. Another giant panda, named Tai Shan, was born in the United States this year on July 9 at Washington's National Zoo.

There are only some 1,600 giant pandas in the wild, all of which live in China's Sichuan, Shaanxi and Gansu provinces.

The San Diego Zoo also hosts Su Lin's father, Gao Gao, and her two-year-old big brother, Mei Sheng.

Su Lin can be seen on a Web cam set up through the zoo's Web site.