Japanese gibbon mystery: Zookeepers reveal how gibbon in isolation became pregnant

A white-handed Gibbon. Photo / 123RF

Staff at a Japanese zoo say they have solved the mystery of Momo the gibbon, who miraculously fell pregnant despite being kept in isolation.

Twelve-year-old white-handed gibbon Momo, who lives at the Kujukushima Zoo & Botanical Garden, stunned zookeepers when she gave birth in 2021.

Vice News reports that, while she did have male neighbours, their cages are separated by bars and chicken wire fences.

They turned to science to solve the dilemma, analysing DNA taken from hair and stool samples to track down the daddy.

“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 superintendent, told Vice.

This week they announced that they had found their man: Itoh, a 34-year-old agile gibbon.

Agile indeed.

Despite the lack of video evidence, the zoo believes they know how the child was fathered.

A hole in the wall.

Measuring 9 millimetres in diameter.

The perforated wall separated Momo’s cage from an exhibition space that Momo and Itoh took turns occupying.

“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 told Vice.

The zoo now plans to try and move Itoh in with his family - and they have replaced the perforated wall with something more solid.