The government is about to retire most of the chimpanzees who've spent their lives in U.S. research labs.
The National Institutes of Health said Wednesday that it will retire about 310 chimps from medical research over the next few years, saying humans' closest relatives "deserve special respect."
The agency will keep only 50 other chimps essentially on retainer -- available if needed for crucial medical studies that could be performed no other way.
The decision was long expected, after the prestigious Institute of Medicine declared in 2011 that nearly all use of chimps for invasive medical research no longer can be justified. What's not clear is exactly where all the retiring chimps will spend their final days, as NIH said more space in sanctuaries is needed.