Now, the world's best-known primatologist is pleading with scientists to give them something back. Like a real home where they can live out the rest of their lives as chimpanzees rather than test subjects.
Jane Goodall, along with the Nonhuman Rights Project (NhRP), is lobbying to have the chimpanzees moved from their current home - a kind of warehouse at the University of Louisiana run by the New Iberia Research Center - to an animal sanctuary.
"I have been following for some time now the sad lives of both Hercules and Leo, and I really urge New Iberia to release them to sanctuary so that they can live out the rest of their lives in dignity," Goodall said in a video statement sent to The Dodo. "And, surely, there can be no good reason to prolong their lives of servitude. So please, I beg of you, do the right thing."