23-year-old giant panda gives birth to twins

Zookeepers never expected the 23-year-old giant panda to give birth again when she was moved to a nature reserve in southwest China to live out the rest of her days.

But Haizi started showing interest in courtship this spring, resulting in a blind date with a male panda suitor and -- four months later -- twin cubs that have made her the world's oldest panda mom, China's Giant Panda Conservation and Research Center announced Thursday.

A 23-year-old giant panda is equivalent in age to an 80-year-old human.

To take care of the senior pregnant panda, the center allocated a special vet and breeder and tailored a breeding program for her, Xinhua news agency said.

Haizi gave birth to a 175-gram (6 ounces) female and a 123.1-gram male on July 30 at southwest Sichuan Province's Wolong National Nature Reserve, where 21 panda cubs have been born this year, the center said.

According to the center, female pandas reached sexual maturity at seven to eight years old, and the reproduction period lasts for 12 years. Captive female pandas over 20 years old are generally not encouraged to reproduce.

Haizi last delivered a pair of panda twins when she was 19 years old.?

In Chinese culture, a set of boy-girl twins are called "dragon-phoenix babies."

"Generally, the maximum breeding age for giant pandas is 20 years old, and pandas older than that are not encouraged to participate in breeding," Li Desheng, a giant panda expert at the breeding center, said in a statement.

"But Haizi's success demonstrates the advanced degree of care offered at our center -- it is a breakthrough in panda breeding."

Summer is the peak season for giant panda reproduction.