After 40 years in the exotic animal care business, Martine Collette, director of the Wildlife Waystation in Tujunga said the savage and bloody attack on a San Gabriel Valley couple by two chimpanzees was the "worst attack by chimpanzees" that she had ever heard of.

St. James and LaDonna Davis were attacked March 3 by two chimpanzees, Buddy and Ollie, as the couple prepared to celebrate the birthday of their adopted chimp, Moe.

The two chimps inexplicably mauled and mutilated the 62-year-old St. James Davis, who lost an eye, part of his nose and suffered severe damage to his cheek and lips in the attack. The chimps also bit off all of St. James Davis' fingers, his left foot, his testicles and damaged his buttocks.

Prior to the attack on St. James Davis, the chimps bit off LaDonna Davis' thumb, said officials with various agencies, among them the state Department of Fish and Game, and sheriff's deputies in Kern County confirmed that the attack and subsequent injuries occurred but declined to comment further.

A spokeswoman for Loma Linda University Medical Center, where LaDonna Davis was treated and St. James Davis was admitted, would only say that St. James Davis was in critical condition.

"It is absolutely not common," Collette said of the attack.

The couple's now 39-year-old chimp was under Martine's care for a number of years after that chimp attacked a person at the Davis' West Covina home six years ago. Moe was never allowed to move back into the home, although they visited the animal regularly in Tujunga and had petitioned for his release for years prior to his transfer to the wildlife retreat Animal Haven Ranch in the community of Caliente in Kern County.

"In a normal chimpanzee attack, a person might lose a finger or two or get bitten. This kind of aggression doesn't usually happen. I don't know what happened in that place, but things like that don't happen without a reason," Collette said.

It was known that the Davises preferred the Kern County facility to the Wildlife Waystation because they could stay there occasionally and be with Moe, who nevertheless remained caged. It was not immediately clear how the two chimps involved in the attack managed to gain access to the Davises, who were reportedly presenting Moe with a cake for his birthday at the time of the incident.

Workers at the ranch shot and killed the two animals, but not before St. James Davis had been severely mauled. Officials this week were still attempting to piece together the reasons why Ollie and Buddy teamed up on the couple.

"We are having necropsies [the examination of a carcass to determine the cause of death and possible physiological changes] performed on them to find diseases or anything else that would cause this kind of behavior," said Troy Swauger of state Fish and Game.

The couple brought Moe to America from Africa in the mid-1970s after the chimp's mother was killed by poachers. They taught him to make sandwiches, brush his teeth, use a toilet -- even sell Girl Scout cookies. The Davises made headlines in 1999 when the animal was confiscated after biting off part of the finger of a woman who was visiting their home and had stuck her hand into Moe's cage.

The year before that, Moe had escaped into the community after being accidentally shocked. A West Covina police officer who responded to that call was bitten by the chimp. Swauger said Moe would remain at Animal Haven Ranch.

An adult chimp weighing 160 pounds has the strength of six to seven adult men, according to experts. Man's closest genetic relatives, chimps share 98.4 percent of the same DNA as humans. And like sometimes unpredictable humans, Collette said that chimps process opinions the same way that people do and act on those feelings.

"Chimps are capable of the same type of emotions as people," said Collette. "They go through jealousy, envy and hatred. They can plan and plot. They are very capable of disliking specific individuals. It's just like if two people walk into a party... they don't necessarily know each other, but based on body language and other factors they form opinions."

According to Michael Dee, general curator for the Los Angeles Zoo and Botanical Gardens, chimps are not naturally aggressive, but they can be if they feel frightened or threatened, and they will defend themselves.

The hands and teeth of a chimp are designed to climb trees, so "they have tremendous strength in their fingers and teeth," Collette said, adding that it is not unusual for other chimpanzees to join an attack in progress.

Dee also said that most likely the animals that attacked the Davises were born in captivity. An LA Zoo spokesperson said chimps haven't been taken out of the wild in more than three decades, meaning almost all chimps living in captivity today were born to it. Of the 16 chimpanzees living at the LA Zoo, 14 were born in captivity.

It is still unknown why the two chimpanzees were free to roam the grounds at Animal Haven Ranch prior to the attack.

A spokesperson for the animal shelter declined to comment, directing inquiries to the Kern County Sheriff's Department, which directed calls to the California Department of Fish and Game.