SAN DIEGO -- The escape was noticed about 3 p.m., Christmas Day, 10News reported.

The monkey, named Chieh, was found high in a tree at the next-door Theodore Roosevelt Junior High School on Park Boulevard.

The Francois' Langur was found in a eucalyptus tree, which produces leaves poisonous to the species.

Zoo officials decided to tranquilize the monkey to get him back into his cage, said Christina Simmons of the zoo.

Francois' Langurs, also known as leaf monkeys because that is mostly what they eat, were declared an endangered species in 1976. They have long dark fur, with white sideburns; adults are only about 22 inches tall and weigh just 15-20 pounds.

The San Diego Zoo is among the few that has a breeding colony of Francois' Langurs.

Chieh was reported in good condition Saturday night after his capture, Simmons said.

San Diego Zoo officials are investigating how the pint-sized monkey got out of his cage.