SAINT JOHN, N.B. - Officials at the Cherry Brook Zoo in Saint John, N.B., made a desperate plea Wednesday for the return of a stolen baby monkey.

Police said someone jumped a fence, kicked in a door at the monkey house and made off with a young callimico monkey named April.

Zoo Director Len Collrin said it appears whoever took the small, black primate, also known as a Goeldi's monkey, knew what they were doing.

"They walked by a Golden Lion tamarind and went into the third enclosure, let the monkeys out and actually locked two back in,'' said Collrin.

"One was still running around in the back hallway and last year's baby was missing.''

Collrin said the monkey is 12-inches tall and weighs less than a pound, adding that it is a high maintenance animal that requires a special diet and won't make a good house pet.

"There's a lot more to looking after a monkey than just feeding it,'' he said.

"They're not a whole lot of joy. They're not toilet trained and they do require special diets.''

Callimico monkeys are a reclusive and diminutive species native to South America.

Discovered a century ago by Swiss naturalist Emil August Goeldi, the animals are now considered an endangered species in the wild.