The only surviving Proboscis monkey at the Netherlands’ Apenheul zoo is being returned to Singapore because it is lonely, the primate centre said on Friday.

Apenheul had five of the long-nosed primates as part of a captive breeding programme. Three died earlier and the female, named Bagik, died at the beginning of May.

‘Jeff is now alone and this is not a natural condition because Proboscis monkeys live in groups,’ the zoo said in a website statement. ‘We have discussed the situation with the zoo in Singapore where Jeff originally came from and decided to send him back so he can live with others of his kind.’

The Apenheul was the only zoo outside Asia which had Proboscis monkeys. Jeff and the other monkeys which died arrived at the centre in 2013.