nobuhiro yada was one of the staff who kept a close watch on her. steadily, she began to grow. >> translator: we didn't think she'd survive, so we were very happy. >> reporter: miyuki's mother had been under when she gave birth and she's showed no interest in her baby been when yamada tried to introduce her to miyuki, she didn't recognize her at all. the zoo staff decided to raise miyuki themselves. when she was about a month all, their mother noticed there was something strange about her vision. it. >> translator: like human babies humans commute with their mothers by eye contact with you miyuki's doesn't seem to be functioning properly. >> reporter: she also falls over a lot because the right side of her body is weaker than the left. professor hidekki takeshida studies the physical and mental development of chimpanzees in comparison with humans. >> in human terms, miyuki has cerebral palsy. the right and left sides of her body are growing unevenly. her growth rate is extremely slow. >> reporter: miyuki always tends to use her left hand as it's her