Having transformed a cow pasture into an African savanna and 500 acres of Central Florida into yet another theme park, the Walt Disney Co. is about to unveil the most un-Disney of entertainment: an amusement park that relies on live animals rather than fake ones.

Animal Kingdom, scheduled to open at Walt Disney World here on Tuesday, features the usual trappings of Disney parks. But unlike others, its star cast consists of about 1,000 real animals that do not always perform on cue, have drawn protests from animal rights groups and are being investigated by federal regulators.The investigation by the U.S. Department of Agriculture into possible violations of the Animal Welfare Act came after at least a dozen of the animals, some of them endangered species, died since last September.

Animal and zoo experts said most of the deaths were explainable and not unusual in a large new park.

But the federal investigation and criticism by animal rights advocates who oppose Animal Kingdom on principle have tainted the publicity blitz that are accompanying the theme park's inauguration next week.

In Animal Kingdom, Disney has lost four cheetah cubs, two hippopotamuses, two rhinoceroses, two Asian small-clawed otters and two West African crowned cranes. The cheetahs died of kidney failure consistent with exposure to ethylene glycol, a chemical used in antifreeze, and their deaths remain a mystery. The other animals died from medical conditions or in accidents.

"Each one is a lesson learned," Diane Ledder, a Disney spokeswoman, said of the deaths. "Animals are unpredictable, and they do things you can't plan for."

Jim Rogers, a spokesman for the Agriculture Department, said the investigation is expected to take several weeks.

He said the department had issued warning letters twice for failure to maintain primate enclosures and failing to maintain adequate veterinary care.