Adelaide Zoo's giant panda fails to fall pregnant for fifth straight year

Australian Adelaide Zoo's female giant panda Fu Ni has failed to fall pregnant for a fifth consecutive year, according to Zoos SA on Wednesday.

Fu Ni and her male partner Wang Wang are the star attractions at South Australia's most popular zoo, but carers confirmed on Wednesday that Fu Ni's pregnancy "window" had passed and that she was not carrying a cub "based on scientific evidence and behavioral observations".

Pandas are notoriously difficult to breed, and despite the zoo' s best efforts, Zoos SA chief executive Elaine Bensted said the "false alarm" will serve to better prepare the zoo in the event she is successfully impregnated in the future.

"Although Fu Ni did not give birth this year, we have every hope that she will go on to become a mother in the future," Bensted said on Wednesday.

"Planning for a potential birth is the furthest we've come to reaching our ultimate goal of celebrating the birth of our own panda cub, and the knowledge and experience gained over recent months will put us in an excellent position to experience success in the future."

Female pandas are typically on "heat" for only three weeks every year, but may be receptive to mating on only a handful of days, meaning the fertility window is open for only one to two days every year.

In an effort to allow Fu Ni the best opportunity to fall pregnant, she is artificially inseminated by zookeepers during the right time -- the latest attempt was made in September last year. Despite 2016 being the fifth consecutive year that Fu Ni has failed to fall pregnant under the watchful eye of zookeepers, an analysis of partner Wang Wang's semen revealed an improvement in quality - something Bensted said could result in Fu Ni falling pregnant next time she is artificially inseminated.

"In another positive development, as part of the artificial insemination process, it was confirmed that Wang Wang's semen quality has improved significantly compared to previous years to the stage that we're confident that he is fertile," she said.

"This provides the team with confidence for coming breeding seasons."