Mystery Solved: How an Ape Living Alone in Her Cage Had a Baby

The Ape (gibbon) living in a cage had a baby. Credit: MatthiasKabel / Wikimedia Commons / CC BY 2.5

After a long and winding mystery, the Kujukushima Zoo & Botanical Garden in Nagasaki has solved one of its most perplexing puzzles yet – how Momo, a white-handed gibbon living solo within her cage, managed to conceive.

Momo became pregnant in 2021 and later gave birth. The zoo announced the newborn gibbon’s gender and stated, “Just so everyone wants to know “who’s the dad” hasn’t been found out yet because we haven’t done DNA testing, but we found out the gender is male” on their Instagram account not long after the birth.

Took 2 years to solve the mystery

After a two-year mystery of Momo’s paternity, the zoo finally uncovered who fathered her child. Through DNA testing on hair and feces samples from both mother and four potential fathers – including Itoh, an agile 34-year-old gibbon at the park – they revealed him as the father.

“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,” Jun Yamano, the zoo’s superintendent, said.

Mated through a hole in the wall

Momo and Itoh delighted zoo-goers with alternating morning and afternoon displays held in two adjacent areas.

A perforated board served as a partition between the two areas in the hopes that it would prevent the apes from engaging with one another.

Yamano told Vice that the couple likely mated through a nine-millimeter-diameter hole in the wall on one of the days that Itoh was present at the exhibit.

How do gibbons select their mates?

Gibbons may not be the first animal that comes to mind when thinking of lasting relationships, but they actually have a remarkable dynamic.

These apes are part of the Hylobatidae family and mate for life with an unmistakably human-like complexity: breakups, make-ups, cheating- they’ve got it all.

The only thing missing from their connection is kisses or hugs; these gibbons show affection through mutual grooming instead.

To ensure that its gibbons are compatible companions, the zoo takes a unique approach: through trial and error, it helps them get to know each other on an individual level.

Reuniting Itoh, Momo, and baby gibbon

Yamano announced the zoo’s intentions to give Momo and Itoh a chance at parenthood, granting them their own space to raise their newborn.

‘They have to get used to each other first. But hopefully, they live together as one family,’ he said.

The zoo said that the unnamed newborn ape currently weighs about 4.4 pounds (2 kilogram) due to Momo’s careful attention.

Gibbons among endangered species

With five species at risk of extinction and fourteen in danger, the global population of gibbons faces a serious threat.

Yet determined conservationists have made strides to protect these small apes from decline.

From Cambodia to Viet Nam, “IUCN Save Our Species” is working hard towards preserving their populations for years to come – despite the difficult challenge this presents.