A zoo has been placed on amber alert after a gibbon escaped from its cage.
Visitors at Paignton Zoo were evacuated as keepers "ran around like crazy" desperately tried to locate the small ape.
The park had reopened its doors just hours before the animal escaped, after a two-week closure due to bird flu.
Staff had been working hard to reopen the zoo in Devon after a dead pelican was found on August 28.
"We have all been evacuated now but there's zoo workers running around like crazy," a witness told Devon Live.
"When I was leaving, at about 1.40pm, there was one escaped gibbon so staff were preventing visitors from using one of the pathways," another witness said.
"It was near the entrance and exit so they had to temporarily stop people coming in which was a shame on their first day back.
"I left via the staff exit. I gather it was a large gibbon. A staff member told me it wasn't dangerous so it was amber alert."
Staff are still trying to get the gibbon back into its enclosure, according to the zoo.
A Paignton Zoo spokesperson said: "Earlier today, a gibbon escaped from its enclosure here at Paignton Zoo.
"As a precautionary measure zoo visitors have been evacuated from the area in accordance with our well-rehearsed escaped animal procedure.
"Zoo staff regularly carry out escape drills and follow a strict protocol for dealing with events such as this. Staff are currently working to return the animal to its home."
Following the discovery of bird flu at the park, staff worked with the Animal and Plant Health Agency and Defra, implementing measures before it was allowed to reopen.
The virus was "primarily a disease of birds and the risk to the general public's health is very low," according to the Defra website.
There are more than a dozen recognised species of gibbons ranging from north-eastern India to southern China to Borneo.
All species are tailless and have long coats varying in colour from cream to brown and black.
The largest species are known as siamangs, and can grow to 29 pounds.
Smaller species reach only about nine pounds.