"Our pandas continue to draw huge crowds," said Lisa Stevens, senior curator of the zoo's giant panda exhibit which is home to the Chinese pandas.

After 9 a.m. local time, a zoo worker with a manual counter designated Matthew Furda, 6, a kindergarten pupil at St. Jude Elementary School in Rockville, Maryland, as the landmark visitor.

In addition to winning prizes, Furda's name will be engraved on a brick to be used in construction of an expanded permanent panda exhibit that will open in 2003.

Since their arrival from China on December 6 last year, each panda has gained about 12 kilograms, eating about 23 kilograms of bamboo daily along with carrots, apples and special biscuits. Tian Tian, the male, will be 4 years old in August, while the female, Mei Xiang, will turn 3 years old in July.

The two joined five others of their species in the United States, three at the San Diego Zoo and two at the Atlanta Zoo.

The pandas, both born at the Wolong Giant Panda Reserve, are on loan to the Washington National Zoo for scientific research purposes in accordance with an agreement reached between the China Wildlife Conservation Association and the U.S. zoo.

Chinese and American scientists are working together to develop an international breeding program to protect the endangered pandas, and the arrival of the two pandas, part of the program, is aimed to provide research opportunities for U.S. zoologists.

In 1972, China sent two pandas to the Washington National Zoo, a gift from the Chinese government following President Nixon's visit to China that year. Ling-Ling died of heart failure in 1992 at the age of 23, while Hsing-Hsing died of kidney disease in 1999, aged 28.

Ling-Ling and Hsing-Hsing produced five offspring, but none lived longer than four days.

There are only about 1,000 pandas in the world now, most of them living in the mountains of the Sichuan Basin. The Wolong Reserve is a major habitat of the endangered species.

(Xinhua 05/04/2001)