Dr. R. Allen Gardner, the American ethologist who trained a chimpanzee to use sign languageDr. R. Allen Gardner, the American ethologist who trained a chimpanzee to use sign language ...

A chimpanzee’s “sweet faces” graced the exhibits at a Michigan zoo for nearly a quarter century, and for decades more at two other zoos. Peggy, the 55-year-old chimpanzee at John Ball Zoo ...