SPRINGWATER, Ont. -- Ontario Provincial Police say they believe a tortoise and a gibbon stolen from a central Ontario zoo a week ago are probably in Quebec.

Sgt. Peter Leon says the OPP are working with Quebec provincial police, as well as officers in Montreal and Ontario's York Region, in an effort to locate the missing animals.

The lemur that was taken at the same time as the other animals was returned to the zoo Tuesday afternoon after being located early Sunday morning in a cage abandoned by the side of a road in Quebec.

Police allege JC the lemur, along with Stanley the tortoise and Agnes the gibbon, were taken from Elmvale Jungle Zoo northwest of Barrie, Ont., late on May 28 or early May 29.

Two men were arrested last Friday -- a 21-year-old from Ottawa and a 20-year-old from Mount Albert, Ont. -- and charged with break and enter, and theft over $5,000.

In a video appeal on Tuesday, Leon says the zoo's owners are particularly concerned for the gibbon, which they say needs the companionship of other gibbons or she could become depressed and stop eating.

"We cannot express how life-threatening it is for Agnes to be away from here," Michelle Persi, a member of the family that owns the zoo, said Tuesday in the video appeal.

"Gibbons can get depressed easily if they are not with another gibbon ... they stop eating, they stop drinking," Persi said as she held Agnes's companion.

Leon called on people in Quebec to spread the appeal on social media.

"Our investigation leads us to believe that there is a strong likelihood that the remaining animals, Agnes the gibbon monkey and Stanley the tortoise, could very well be in the province of Quebec," he said.

The Springwater, Ont., zoo houses just over 300 animals, and had only been open for a couple weeks this season when the animals were taken.

- With a report from CTV Barrie's Mike Arsalides