City officials say the zoo's general manager, Bruce Dougan, got an anonymous call, telling him they knew where the monkey was.
Dougan was able to pick up the monkey at a location outside the zoo, officials said.
The monkey, named Hercules, is currently being checked over and will be monitored, the said.
Hercules, 19, was taken from the zoo's monkey exhibit overnight Tuesday, the general manager had said.
The lock on the exhibit was found cut Wednesday at 8 a.m. during a routine check by security.
“This is a terrible situation and all we want is for the squirrel monkey to be returned to us safe and sound,” Dougan had said.
It's unclear how the theft occurred because the 40-acre zoo has security, including a dog, he said.
The zoo normally has six squirrel monkeys, including Sheldon, who made headlines last year as the orphaned monkey who had to be rushed to the Atlantic Veterinary College in Charlottetown when his mother died the day after he was born.
Hercules is the patriarch of the group.
Physical, physiological concerns
"We're concerned about his physical well being and its health because these animals have a very specific diet and we're concerned about what kind of food and care this animal is going to be receiving now that he's not here," Dougan had said.
"You know he's going to be very stressed because he's away from his troop, he's in unfamiliar surroundings with unfamiliar people and so we're very concerned about physiological well being as well."
Inexperienced people should not be handling these animals, Dougan had stressed.
"They can bite and any animal's mouth is full of bacteria, so there's always worry about infection and with very small children, they could probably give them a fairly serious bite."
Squirrel monkeys are the smallest of the primate family Cebidae and are typically found in the forests of southern North America and South America.
They usually weigh between one and 2.5 pounds and have an average lifespan of 15 to 25 years.
The zoo's website says they are threatened by habitat destruction, illegal hunting and capture for the pet trade or medical research.
In April 2008, a young Callimico goeldi monkey was stolen from the Cherry Brook Zoo in Saint John.
The nine-month-old South American marmoset named April was found a couple of days later after police received an anonymous tip. She was in a blue plastic box behind a building near a gas station in the Bayside Drive area.