LOS ANGELES -- A chimpanzee who is toilet-trained and can eat with a knife and fork is believed to be on the loose in a Southern California forest.

The 42-year-old chimp called Moe disappeared Friday from Jungle Exotics, which trains animals for the entertainment industry. The chimp wandered into a house next door, surprising construction workers who then saw him head for a nearby mountain, reported KNBC-TV in Los Angeles.

A weekend search in the San Bernardino National Forest 50 miles east of Los Angeles came up empty.

His distraught owners, LaDonna and St. James Davis, said they are devastated at Moe's disappearance. The Davises on Monday appealed for tracking dogs that may be able to follow scent from Moe's blankets.

"He's a nice animal," said LaDonna Davis. "He deserves to be safe, and he's not."

The couple urged the public to not approach the 42-year-old chimp because he might become fearful and aggressive.

"We think he may be hunkered down near a water source," said Mike McCasland, a friend of Moe's owners. "We think he's in a contained area a quarter-mile away, but he's probably disoriented and the brush is extremely heavy."

The Davises, who raised Moe in suburban West Covina for more than three decades, contracted a helicopter to fly over the forest Saturday and Sunday, hoping the noise would flush Moe out of hiding, said McCasland, who's serving as their spokesman.

"That's the one thing that does spook him," he said.

Searchers were also making noise and calling Moe's name as they scoured the forest.

"His survival instincts would probably kick in, even though he's been in captivity for a long time," McCasland said. "He could literally survive up there for a long time."

The biggest danger to the chimp would be rattlesnakes, he said.

San Bernardino County officials were not involved in the search because the chimp did not pose an immediate threat to public safety, but Moe's escape will be investigated, said Brian Cronin, chief of the county's Department of Animal Control and Care Services.

"It's our impression that this was just an error," he said. "Jungle Exotics has always had exemplary ratings."

Jungle Exotics had no comment on Moe's escape. A woman who answered the phone referred calls to McCasland.

Moe's disappearance is the latest in a long line of headlines involving the chimp over the years.

A member of the merchant marine, St. James Davis brought Moe home from Tanzania in 1967 after the baby primate lost his mother to poachers.

He and his wife were unable to have children and treated Moe as their surrogate son, toilet-training him, teaching him to eat with a knife and fork and letting him sleep in their bed and watch TV.

But local authorities didn't view Moe in the same light. For years, the Davises waged a legal battle to keep Moe in their home.

They finally lost in 1999 when Moe bit part of a woman's finger off when she inserted her hand in his cage. The Davises said he mistook her red-painted fingernail for his favorite licorice. The incident also came after Moe mauled a police officer's hand.

Over the Davises' protests, Moe was taken to an animal sanctuary in Kern County where the couple visited him regularly. But in 2005, when they took a cake to celebrate Moe's birthday with him, the couple was viciously attacked by two other chimpanzees who had escaped their cages.

The chimps nearly killed St. James Davis, chewing off his nose, testicles and foot and biting off chunks of his buttocks and legs, before the sanctuary owner shot the animals to death.

Moe, who has appeared in movies and TV shows, was transferred to Jungle Exotics where the Davises built him a state-of-the-art cage, McCasland said.

"He's a very personable, sweet, nice chimp," McCasland said. "He's not going to be aggressive unless he's provoked."