A baby orangutan has been described as a “wonderful surprise” after its mother returned a negative pregnancy test.

The newborn Bornean orangutan arrived to mother Leia and father Willie on June 18, and has been hidden away with Leia since birth.

Keepers at Chester Zoo have said that the infant is “bright, alert and suckling well”.

Chris Yarwood, a primate keeper at the zoo, said: “The pregnancy tests we had carried out on Leia in the months prior to the birth had actually returned negative results.

“It was therefore a wonderful surprise to arrive one morning to see her protectively cradling a beautiful new arrival.”

“Leia enjoys spending lots of time alone with her baby and has so far been quite shy about showing it off,” Mr Yarwood said.

“She always keeps it really close to her and so we’ve not yet been able to clearly determine what the gender of the infant is.

“What we are sure of though is that the baby is bright, alert and suckling well from mum and has developed well over the last couple of months.

“This is Leia’s second baby – she’s a great mum and is doing a fab job once again.”

Bornean orangutans are listed by the International Union for the Conservation of Nature as critically endangered in the wild, with only 55,000 individuals estimated to remain on the island of Borneo in Indonesia.

“Chester is one of the few zoos in Europe that cares for both Bornean and Sumatran orangutans,” Mr Yarwood said.

“These are critically endangered animals and, importantly, we’ve seen babies from both sub-species born in recent times.

“It just goes to show that, despite all of the uncertainty in the world right now, life is carrying on as normal for the orangutans, which is really uplifting to see.”