A monkey-hunt is underway in the San Francisco area after someone stole a tiny squirrel monkey from the city's zoo.

The black and orange monkey, named Banana Sam, was reported missing from his enclosure by zoo employees Friday morning. Zoo officials quickly found signs of a break-in: two holes cut in the wire mesh cage and the chain on the perimeter fence cut.

"The one hole is fairly small and its right by where their nest box is that they sleep in at night. The other hole on the other panel is fairly large - a small person could certainly go in," said Corinne Macdonald, the curator of primates at the San Francisco Zoo.

Now, the search is on for Banana Sam, who is one foot tall and weighs only two pounds. At 17 years old, Sam is considered elderly by monkey standards and he requires special food to survive.

A private donor has put up $5,000 for Banana Sam's safe return.

Banana Sam has apparently taken to Twitter, tweeting at the handle @SF_BananaSam.

"OMG YOU GUYS RAINFOREST CAFE IS NOT WHAT IT SOUNDS LIKE. It's basically an Applebee's with a "Sounds of the Jungle" CD playing. I'm out," read one post yesterday.

"I'm a funny-looking vegan who ran away from home and who people follow on Twitter. IN other words, A NORMAL SAN FRANCISCAN," read another post.

"Do you know any stores in SF that sell female squirrel monkeys? Asking for a friend," read another post.

Squirrel monkeys are often sold on the black market and used for medical research or kept as exotic pets.

As one San Francisco cop said, if your friend, relative, neighbor or acquaintance suddenly has a pet monkey they didn't have the day before, please call 9-1-1.