ZOOKEEPER DISCOVERS HOW ISOLATED GIBBON GOT PREGNANT
When Momo, a gibbon, became pregnant two years ago, officials at the Japanese zoo where Momo lives scratched their heads. The 12-year-old gibbon lives alone in an enclosure, so it's unclear exactly how she became pregnant. Now, thanks to DNA evidence, the mystery has been solved. Female white-handed gibbons certainly have neighbors, but are separated by two barriers. This made it difficult for zookeepers to understand what had happened. For several years they have been trying to collect DNA samples from a male gibbon she gave birth to in 2021. But Momo, of course, was protective of her child and wouldn't let them get close enough to collect a sample.
Finally, they were able to obtain samples not only from Momo's son, but also from Momo herself and four potential fathers living nearby. Now that the results are in, it can be said with certainty that Ito, a 34-year-old nimble gibbon, is the father.
DNA has solved one mystery, but Kujukushima Zoo and Botanical Gardens still have to figure out how the gibbons mated. There is no CCTV footage of what happened, but zookeepers believe it was caused by a small perforated board separating Momo's fence from the display area.
Ito and Momo take turns leaving the exhibition hall in the morning and afternoon. The board is designed to prevent mating, but has a 9mm hole. And surprisingly, employees believe this is how they reproduce. Zoo director Jun Yamano said, “I think one day when Ito was in the exhibit, he most likely mated through the opening.”
To attract Momo, Ito had to go through several obstacles. Gibbons is known to be picky about his mates, which is one reason the staff were so shocked by what happened. These monogamous animals select mates based on appearance, social behaviour, and complex vocalisations.
Now that the zoo has intact family photos, they are slowly working to get Ito to join Momo and her son.
“First we have to get used to each other. But I want them to live together as a family," said Yamano.
Meanwhile, zoos no longer risk unexpected pregnancies. Perforated boards are now replaced with non-perforated partition walls.