In an attempt to protect his "girlfriend" and baby, the male Japanese monkey, nicknamed Samurai, has already expropriated a dozen expensive mobile phones, the spokesman said.
"Samurai never feels shy about swiping phones from an owner's hands and then hiding them in his cage," he said.
Zoo workers have managed to return some of the mobile phones intact their rightful owners, but some are in need of repair, he said.
Officials have put up a warning sign for visitors: "Dear biological relatives, we regard phones, cameras and video cameras as our property - we take and destroy them."
But the photographers, who are usually clueless as to what the strange note means, insist on taking pictures of the adorable primate, wholly unaware of its larcenous habits.