Finally, after more than four decades of public service, it’s retirement time for Rita.

The 47-year-old chimpanzee, brought to the United States from Africa by the U.S. Air Force in the 1950s, is a prime candidate for a new retirement home to be built near Shreveport, La. The facility is expected to cost at least $35 million, most of it federal money, to build and operate over a 10-year period.

Under a $19 million contract awarded Monday by the National Institutes of Health, Chimp Haven Inc., a nonprofit group based in Shreveport, will operate “a sanctuary system for all chimpanzees retired from federal biomedical facilities,” the group announced. Chimp Haven said it plans to contribute $6 million in matching funds.

The chimpanzee retirement community is to be built on 200 acres of forested land donated by Caddo Parish, La., and is scheduled to open by spring 2004. NIH said it also plans to provide about $10 million to fund construction of the sanctuary, including administrative offices, infrastructure, utilities, an education center, quarantine facilities habitat for 200 chimpanzees. Eventually, the sanctuary is to be expanded to accommodate more than 300 chimps.

Proponents of the project said it will save taxpayers money in the long run because the cost of keeping chimpanzees in research labs is about double the cost per animal of harboring them in the sanctuary. According to chimpanzee advocates, there are 1,300 to 1,600 federally owned or supported chimpanzees in biomedical laboratories, including 600 to 900 who are eligible for retirement.