Guests at Paignton Zoo had to be evacuated and others were put into lockdown after a monkey escaped its enclosure.
Eyewitnesses claimed a "code red" was put into place before it was downgraded to a "code amber" on Tuesday 22 August.
Visitors to the popular attraction were moved from certain areas and others were told to stay inside a restaurant after the animal broke free.
It was later captured by staff and an investigation into the incident has now been launched.
A spokesperson for Paignton Zoo said: "Earlier today, staff at Paignton Zoo had to attend to an incident involving an escaped monkey.
"As a precautionary measure, zoo visitors were evacuated from the area in accordance with our well-rehearsed escaped animal procedure and the animal was re-captured without incident shortly after the alert was raised.
"We are currently investigating how this incident occurred and would like to thank everyone who was at the zoo this morning for their patience and cooperation."
It is not yet known what type of monkey escaped.
Two gibbons escaped from their enclosure at Paignton Zoo last in September last year.
It happened just hours after the site reopened to the public following a two-week closure because of an outbreak of bird flu.