Primate keepers threw a gender reveal party for the zoo's newest addition and added two enrichment boxes packed with coloured plastic children’s balls, hay and tasty treats into the gelada’s indoor den.

It didn’t take long for the 13-year-old alpha male and adult female, Tana, to tip out blue balls and reveal the news it’s a boy - and his fourth son.

The youngster, who was born to mum, Addis, on December 21 has been named Dendi by keepers, after Mount Dendi, the second highest volcano in Ethiopia, the native home of the species.

He joins brothers Billie, Gimbi and Ambo – who spent hours afterwards playing with the ball pit balls – as well as adult females Jimma and Tana in their award-winning half-acre natural hillside enclosure on the lower zoo site.

The geladas form part of a European Endangered Species Programme and keepers have been successfully breeding them since 2014. Gestation is usually around six months and mothers will carry the baby on their stomach for the first few weeks, before transferring it to their back.

The youngster will begin to gain more independence around five-months-old.