A female monkey becoming pregnant in her own cage at a Japanese zoo left staff scratching their heads for two years but finally the mystery male has been discovered.
Momo, a white-handed gibbon at Kujukushima Zoo and Botanical Garden, Nagasaki, gave birth in February 2021.
But with no males in her cage it sparked an investigation by zookeepers which involved examining excrement but as the new mum was extremely protective of her offspring, it took two years to gather samples for a DNA test.
Finally the dad was found to be Itou, a 34-year-old agile gibbon but still staff were puzzled at how the two monkeys had managed to find time together as they were in separate cages.
Momo was living in a cage with large bars that were also covered by chicken wire and boarding which separated her section with that belonging to Itou.
But closer inspection showed that there was a hole in the boarding no more than around 9mm and staff now believe that the two were able to mate through it - although it is still only a theory.
The boarding has now been replaced by a steel barrier but there are plans for Momo and Itou to move in together with their baby but staff will need to do it gradually so that the couple can get used to each others company.
Jun Yamano, zoo superintendent, told Vice News of how it took so long in the first place to get the DNA sample.
"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," he said. "We think it’s very likely that on one of the days that Itoh was in the exhibition space, they copulated through a hole."
He reinforced that it is important that the monkeys are comfortable living with each other first before they can be in the same enclosure.
Yamano said: "They have to get used to each other first. But hopefully they [will] live together as one family."
