Keepers at Tokyo's Ueno Zoo said they have high hopes for the meeting between 16-year-old Shuan Shuan, from the Chapultepec Zoo in Mexico City, and Ling Ling, the Ueno Zoo's last living panda.

It is the first time a female panda has come to Tokyo, although 18-year-old Ling Ling has made three trips to Mexico in a quest for the patter of tiny paws.

Beijing-born Ling Ling's sperm was used to artificially inseminate Shuan Shuan and another female in Mexico City earlier this year on his third visit, but neither that nor more conventional attempts at reproduction bore fruit.

Home turf

"This time, Ling Ling will be in his own territory," a Ueno zookeeper said. "The burden on him will be much less."

He said Shuan Shuan will go on heat around March and may stay until sometime in the summer, depending on whether or not the mating is successful.

Pandas are notoriously difficult to breed in captivity, as the females go on heat only once a year and can be picky about partners.