One of two monkeys that escaped from Belfast Zoo was still on the run last night - 36 hours after he first fled his enclosure.
The zoo has admitted it planned to review the enclosure following the second mass macaque break-out in two years.
Zoo staff have asked anyone who has spotted the lion-tailed macaque, Zoid, to contact them immediately.
His comrade Rose was found yesterday afternoon following a search operation involving the zoo vet, keepers, and the Fire and Rescue Service.
Both were also escapees in the 2013 break-out.
They escaped from their enclosure again on Wednesday morning.
Rose was tracked down to what a zoo spokeswoman termed as a "nearby location", and tranquillised by the zoo vet before being returned to her enclosure.
The macaques are native to India, but a zoo spokeswoman said they are "fairly hardy and the cold should not affect them".