In another step toward ending biomedical research on chimpanzees, the National Institutes of Health announced on Wednesday that it would begin the process of retiring most of its chimps to sanctuaries, though it will leave some for possible future research.
The decision, which follows the recommendations of an agency advisory group, does not end biomedical research on N.I.H. chimpanzees. But it calls for retiring about 310 animals that the agency owns over the next few years, to sanctuaries from which they cannot be recalled for research. A colony of up to 50 will be kept at a site yet to be decided in case there is a compelling need to use them in research for human health. And new guidelines will be in place for any future research and for chimpanzee housing.
The N.I.H. decision was long anticipated, and follows a series of efforts to protect chimpanzees, both in the wild and in captivity. Two weeks ago the United States Fish and Wildlife Service proposed declaring captive chimpanzees endangered, requiring permits for their use that would hamper efforts by public or private labs to use the animals to test drugs and in other research.
"Chimpanzees are very special animals," the N.I.H. director, Dr. Francis S. Collins, said in a telephone conference call on Wednesday. "They are our closest relatives." As such, he said, "we believe they deserve special consideration."
Kathleen Conlee, vice president for animal research issues at the Humane Society of the United States, which has pushed the N.I.H. and other agencies for changes in rules regarding chimpanzees, said her group was pleased. "This is a great day for the chimpanzees, and we've seen a number of them recently," she said.
Ms. Conlee said the decisions by the two federal agencies mean "the door will be open, but I don't think anyone's going to try to open it very often."
Sarah Baeckler Davis, executive director of the North American Primate Sanctuary Alliance, which represents eight sanctuaries in the United States and Canada, including the legally designated national chimpanzee sanctuary, known as Chimp Haven, in Louisiana, said her members were committed to providing space for any chimps the N.I.H. wants to retire.
"We want to make it as easy as possible for the federal government to get these chimps the retirement they deserve," she said.
The decision was the culmination of a process that began in 2010 when Dr. Collins commissioned the Institute of Medicine to study the need for chimpanzees in biomedical research.
The retirement plan depends on some changes in legislation to allow the agency more flexibility in spending, but not more money. It was recommended in January by the agency's Council of Councils.
Dr. Collins announced on Wednesday that he was accepting almost all of that group's 28 recommendations, which included strict guidelines for any future biomedical research, recommendations on housing of chimps and the review process for any future research.
The one recommendation the agency did not accept was that each chimp be allotted 1,000 square feet in housing. Dr. Collins said further study was needed, as the available scientific evidence was not clear enough on how much space chimps needed.
This article originally appeared in The New York Times.