Hundreds of thousands owf humans have also evacuated since Merapi began to hurl vast columns of ash into the sky above Java and send deadly super-heated clouds of debris cascading down its slopes.
Nearby villagers told the Antara news agency they fear some of the monkeys were unable to escape the deadly pyroclastic flows, which have also killed about 270 people.
Many of the fleeing monkeys are said to have gone to the slopes of nearby Mount Merbabu, where food and a safe haven are available.
Rescue workers say they have also encountered hundreds of dead cattle and other animals in abandoned villages hit by volcanic debris.
Photo: Saung Sutanto