Within days, 15-year-old Fu Ni will climb her tree – the tree she climbs when she’s just about ready to have sex.
She might bleat, a little like a sheep. It’s her way of flirting. Meanwhile, Wang Wang, 16, will start to twerk around the place, marking his territory.
If Wang Wang tries to get into Fu Ni’s tree before she’s ready, she’ll swipe him away with a grumbling grunt.
Australia’s only two giant pandas are getting ready to rumble. Once a year, a tiny mating window opens. The notoriously sex-shy animals will have about 36 hours to try for a cub.
Dr Phil Ainsley is Adelaide Zoo’s life sciences director and head of the team of panda handlers that have looked after Wang Wang and Fu Ni since their arrival from China in 2009.
Until last year, the team of handlers, vets and reproductive specialists used artificial insemination in the hope of a panda pregnancy.
But thanks to the pandemic, which kept a Chinese reproduction expert out of the country, and a better understanding of the panda (research shows it’s best to just “let them be pandas”), they now see natural breeding as the best option.
And the season is “incredibly close”, Ainsley says, so they’re on high alert.
“As soon as we see Fu Ni climb up her favourite tree, that’s an indication of her oestrus cycle,” he says. “In her natural habitat, that gets her out of the way of other males. She’s in control.
“A male panda will approach and indicate that he’s interested. If she’s not ready, she’ll grunt and swipe at him. When she’s ready, she’ll descend the tree and mate.”
Wang Wang will also do a “panda twerk” as he marks the territory around Fu Ni, spraying his scent.
Giant pandas are no longer endangered, but with just over 1,800 in the wild, they’re still vulnerable. Around the world, panda keepers have met the goal of having 600 in breeding programs.
But giant pandas are not out of the woods yet.
Even if they successfully mate in that tiny window, giant pandas have a gestation period of about four months, but it can stretch to 10 months in some cases.
They have pseudo pregnancies, too. These phantom pregnancies are so realistic that the panda’s behaviour, chemical signals and blood tests all indicated that she’s pregnant.
This has happened to Fu Ni several times. Adelaide Zoo gave her a toy to act as her pseudo cub at the end of the whole process.
Ainsley says if a panda gets pregnant but the environmental conditions are not right, pandas can reabsorb the foetus.
“If there’s a drought, or food isn’t prevalent … if there are stress events, they can reabsorb the foetus as close as three to four weeks before birth,” he says.
If the pregnancy is “real”, the foetus is hard to confirm until just a week or two before the birth – the jelly-bean size creature can be tricky to spot.
For now, Wang Wang and Fu Ni, who are at their peak mating age, are kept fed with 20 varieties of bamboo, while the panda handling team monitor closely and maintain the routines the animals are used to.
There have been stoushes over the funding for Wang Wang and Fu Ni. “Panda diplomacy” is part of Australia’s relationship with China, which has had some recent bumps. In the past it has been suggested that the panda pair’s lack of offspring could get them deported.
But luckily Wang Wang and Fu Ni don’t know about all the pressures outside their enclosure. That means Wang Wang is free to twerk and scent, and Fu Ni can happily climb her tree – and, hopefully, when she’s ready, clamber back down to meet him.