The Mystery Surrounding a Pregnant Gibbon in Japan Has Finally Been Solved!

The mysterious pregnancy of a gibbon residing by herself in a southern Japanese zoo has finally been solved! Roughly two years after giving birth to a male covered in black hair with a fringe of white fur trimming its face, the paternity of Momo the gibbon’s still-unnamed offspring has been revealed to be — drum roll, please — none other than Itoh, a 34-year-old agile gibbon living at the same zoo.

The Maury Show

For two whole years, the Kujukushima Zoo & Botanical Garden couldn’t wrap its head around the puzzling mystery: How did Momo, a 12-year-old white-handed gibbon that was kept solo in her enclosure, end up pregnant? During her time there, she had never been joined by a male companion. That only occurs if zoos are hoping the animals will mate. So, what gives? Yes, some of her closest neighbors were males, but their cages were divided by bars and chicken wire, making intimate contact impossible for all intents and purposes.

After she gave birth in 2021, that was the $64,000 question on everyone’s mind, as it was unfathomable that Momo and a potential suitor could have successfully mated through multiple protective barriers.

Photo: Pixabay/gayleenfroese2

You ARE the Father!

Finally, with the help of DNA testing, zookeepers identified the male responsible for fathering the baby gibbon, and they think they’ve figured out how the two likely got to be parents. Using stool and hair samples collected from Momo, her baby, and four potential baby daddies, it was announced on the last day of January that the identity of the father was, in fact, Itoh, a 34-year-old agile gibbon.

“It took us two years to figure it out because we couldn’t get close enough to collect samples — she was very protective of her child,” zoo superintendent Jun Yamano told VICE World News. Okay, great. One mystery solved but still one to go: How/when did they get the time alone?

white-handed gibbon
Photo: Pixabay/strichpunkt

Where There’s a Will…

Without surveillance footage, educated guesses are the best the zoo has to go on, but its hypothesis boils down to a glory hole measuring just under 3/8 inch in diameter located in a partition wall. Ouch!!!!!! So, here’s how it could have gone down.

Momo and Itoh each take turns going on display in an exhibition area located in front of Momo’s enclosure. That space and the display area are separated by a perforated partition to prevent the monkeys from physically interacting. The two gibbons are rotated morning and afternoon. 

“We think it’s very likely that on one of the days that Itoh was in the exhibition space, they copulated through a hole,” Yamano explained. He added that such mating habits were unheard of. Zoos periodically pair animals to familiarize themselves with one another, but their efforts aren’t always successful. This was something else completely.

Photo: Pixabay/kengkreingkrai

And Baby Makes Three…

According to Yamano, the zoo hopes to move Itoh in with Momo and their offspring sometime soon. “They have to get used to each other first. But hopefully, they live together as one family.” To prevent a repeat performance, the zoo replaced the perforated partition board separating the display area from Momo’s abode with a solid barrier free of openings of any diameter, Yamano stated.

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