She became particularly irritable toward me and Sandy. She would not allow us to approach her, let alone touch her, and she often broke into loud screams if we approached. She also became curiously incommunicative and ignored many of our efforts to sign to her. Lea and I knew well that chimpanzees become difficult when they reach puberty. And yet, we had managed to persuade ourselves that Jennie would be different. We felt we knew Jennie even better than we knew each other. We were wrong.