17:34 24 November 2015
The US National Institutes of Health (NIH) will cease its medical research and will send research chimps to sanctuaries to enjoy their retirement.
The NIH has started retiring its research chimpanzees two years ago. The 50 remaining will be retired before Christmas, as confirmed by NIH director Francis Collins.
Collins said: "I think this is the natural next step of what has been a very thoughtful five-year process of trying to come to terms with the benefits and risks of trying to perform research with these very special animals."
"We reached a point where in that five years the need for research has essentially shrunk to zero."
Upon retirement, the chimps will be sent to Chimp Haven, a government-funded facility in Louisiana that currently houses 208 chimps.
However, some do not agree with the move. Frankie Trull, of the Foundation for Biomedical Research, said: "Given NIH's primary mission to protect public health, it seems surprising."
He added: "I don't understand the decision of 'we're going to take that resource away forever."