It took experts two years to get to the bottom of the confusing case
Japanese zookeepers were left baffled when they realised a female monkey was suddenly pregnant – despite apparently being left alone in her cage.
In 2021, a 12-year-old female white-handed gibbon named Momo surprised zookeepers at Nagasaki’s Kujukushima Zoo & Botanical Garden with an unexpected pregnancy.
At first, the news was seen as nothing short of miraculous. There had never been a male monkey in Momo’s enclosure, or so the experts believed. But nature had other plans, leaving the team astounded by this mysterious turn of events.
When Momo, the endangered white-handed gibbon, gave birth to her adorable baby, the zoo staff was left scratching their heads, trying to unravel the mystery of how this miraculous conception occurred.
On social media, zookeepers openly admitted they were clueless about the identity of the father. They also shared that DNA testing on the newborn had been impossible due to Momo’s fierce protectiveness. In an Instagram post, the zoo shared: “So, for everyone wondering ‘who’s the dad,’ we haven’t figured that out yet because we haven’t been able to do DNA testing, but we did find out the baby’s gender: it’s male.”
What seemed like a miraculous event in the animal kingdom wasn’t exactly what it appeared to be. Two years later, the zookeepers finally revealed the truth behind Momo’s unexpected pregnancy.
Jun Yamano, the zoo’s superintendent, explained the long delay in solving the mystery: “It took us two years to figure it out because we couldn’t get close enough to collect samples—Momo was extremely protective of her baby.”
Firstly, they carried out a DNA test on the baby, and discovered that its dad was Itoh, a male gibbon who was held in a separate enclosure. But love knows no bounds, and a simple thing such as being housed in a separate unit was not enough to keep Momo and Itoh apart.
Yamano told Vice that staff believe the pair were able to mate due to an area next to Momo’s enclosure that both she and Itoh took turns using, while on display to the public.
The investigation found a tiny hole, measuring nine millimetres in diameter, in the board that separated that unit from Momo’s enclosure.
Although the zoo didn’t manage to capture any footage of the copulation, it’s thought the two gibbons were able to get it on while Itoh was inside the display area and Momo was next door on the other side of the hole. Yamano went on to say that the mating and subsequent pregnancy was unprecedented at the zoo, as the gibbons are usually paired together intentionally after being introduced to each other.
They now plan to allow Itoh into the same enclosure as Momo and their baby, and have also fixed the pesky hole in the wall.
