posted February 22, 2013 06:46 PM            

The cause was cancer, said Ed Stewart, her companion and only immediate survivor.

Ms. Derby was among the first animal rights advocates to champion performing animals, especially exotic species like elephants, apes, monkeys, lions and tigers. Though trainable, those animals have never been fully domesticated, and often end up abandoned or ill-treated once their usefulness as performers expires, she contended.

In 1984, Ms. Derby and Mr. Stewart founded the Performing Animals Welfare Society (PAWS) and opened their first sanctuary on 30 acres in Galt, Calif., outside Sacramento, which was the first in the United States equipped to care for elephants. In 2002 they opened a second, more sprawling sanctuary called Ark 2000 in San Andreas, about 40 miles away.

Covering 2,300 acres, Ark 2000 has become a sort of retirement community for more than 100 exotic animals, most of them former film or circus performers, survivors of roadside zoos and former pets whose owners could no longer handle them. The facility is supported by private and corporate donations and a membership list said to number 33,000.

Among the animals there is an elephant, Maggie, who developed arthritis and became depressed after spending several years, mainly indoors because of the weather, at the Alaska Zoo in Anchorage. Two bears at the sanctuary — a grizzly bear named Tuffy and a Kodiak bear named Manfried — were featured in the 1994 film “Legends of the Fall,” set in Montana. They had been sold after the filming and were rescued from a poorly ventilated horse trailer during a Southern California heat wave.

Ms. Derby trained animals for television in the 1960s and ’70s and recounted the experience in a 1976 memoir, “The Lady and Her Tiger.” Neglect and abuse, including violence, food deprivation and chained confinement, were routine among her fellow trainers, she wrote. (Domesticated animals like dogs were usually spared mistreatment. Lassie, at least as portrayed by the dogs she knew, she said, was always treated well.)

Wayne Pacelle, president and chief executive of the Humane Society of the United States, said Ms. Derby’s many years as a witness gave her unique credibility as an advocate, and made her “fearless” in confronting animal abuse in the entertainment world. “Hollywood, Las Vegas casino owners, Ringling Brothers — she took them all on,” he said.

In addition to “Lassie” and “Flipper,” which starred a dolphin, Ms. Derby had worked for shows like “Gunsmoke”; “Gentle Ben,” which was about a bear; and “Daktari,” set in a fictional animal preserve in Africa. In the ’70s she worked on commercials, including a campaign for Lincoln-Mercury featuring the actress Farrah Fawcett and two cougars.

Ms. Derby said she did not find much work as an animal trainer after her memoir was published. “I never ate lunch in that town again,” she told The Los Angeles Times in 1995.

She twice testified before Congress, however, and was appointed to California study commissions whose findings led to state laws restricting private ownership of exotic pets and setting minimum standards for some performing animals.

The laws did not go far enough, she contended. Ms. Derby believed that wild animals should not be in captivity, period — not even in sanctuaries like hers, which she considered a less onerous form of captivity but captivity nonetheless. “All I can do is make their prison as comfortable as possible,” she said.

Ms. Derby was born Patricia Bysshe Shelley on June 7, 1943, in rural Sussex, England, to Charles and Mary Shelley. Her father, a professor of English literature, said he was a descendant of the poet Percy Bysshe Shelley. Patricia, who studied dance, moved to Southern California when she was 19 seeking work in film. From a brief marriage that ended in divorce, she kept the name Derby.