They might not be getting a pension, but one group of federal employees could be looking at early retirement: chimpanzees used in federally funded research.

A working group advising the National Institutes of Health said in a report issued on Tuesday that the agency should retire most of the nearly 700 chimps currently in use and transfer them to sanctuaries. The NIH should also make sure that any chimps that are still used for research are housed properly, the group said.

“Chimpanzees must have the opportunity to live in sufficiently large, complex, multi-male, multi-female social groupings, ideally consisting of at least 7 individuals,” the report said. “Unless dictated by clearly documented medical or social circumstances, no chimpanzee should be required to live alone for extended periods of time.”

The working group's report was drawn up in the wake of a review issued in December 2011 by the Institute of Medicine, an independent nonprofit group, which determined that most current use of chimpanzees in biomedical experiments is unnecessary.

“Clearly there is going to be a reduction in the use of chimps in research," University of California, Davis veterinary researcher and working group chair K. C. Kent Lloyd told reporters, according to ScienceInsider. "I don't believe that will be at the cost of research advances.”

The working group recommended shutting down six out of nine federal grants for biomedical experiments on chimpanzees and five out of 13 behavioral and genomics studies. Any future chimpanzee experiments should only take place if they cannot be done ethically in humans or other animals, the report said.

Overall, the report recommends shrinking the NIH's chimp research to a single colony of 50 individuals within the next five years.

Chimpanzees became obsolete in medical research thanks to a variety of factors. Both modern molecular biomedical technologies and new animal models of disease that can reproduce in large numbers, like the mouse, are faster and cheaper than using large primates.

Plus, the chimpanzee might actually be too hardy to use for researching infectious diseases.

“Over the years, chimpanzees have proven to be quite resistant to many pathogens, whereas in discovery research, the need is for animal models that are relatively susceptible to infection with the infectious agent of concern,” the report said.

The NIH's Council of Councils voted unanimously to accept the report. There will now be a 60-day period for comment before NIH Director Francis Collins decides to officially accept it, according to ScienceInsider.

Animal activists took heart at the news of the working group's report, but some were still reserved in celebration.

“The end is in sight, but we must not stop until all chimpanzees are out of laboratories,” People for the Ethical Treatment of Animals said on its official blog.

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