Ling Ling, a perennially unlucky giant panda in Japan, has once again failed to father an offspring -- even with the help of science.

Keepers at Tokyo's Ueno Zoo said on Wednesday that attempts to artificially impregnate a female panda on loan from Mexico had failed, ending months of anxious speculation.

When female panda Shuan Shuan was brought to Tokyo in December, it was hoped that she and the Beijing-born Ling Ling might click romantically. Sparks were few, so the zoo turned to artificial insemination.

In spring, Shuan Shuan began showing signs of pregnancy, leading panda watchers to hope for the patter of tiny paws.

But the signs, including changed eating habits and nest-building, turned out to be a false pregnancy.

Before Shuan Shuan's Tokyo sojourn, Ling Ling had made three separate unsuccessful trips to Mexico.

The 18-year-old male is one of eight pandas in Japan, and the only panda living permanently at Ueno Zoo.

There are only an estimated 800 to 1,000 pandas left in the wild, and they are notoriously difficult to breed in captivity.

Females come on heat only once a year for a few days, and can be picky about partners.

The news was a disappointment for the Tokyo zoo, the first in Japan to have a panda.

"Pandas are like the symbolic face of the zoo," said spokesman Masanari Ono. "It's a terrible shame that we couldn't breed any this time."

(China Daily via agencies, July 8, 2004)