Koko (gorilla) - Michael and Ndume

Michael and Ndume

Patterson claims that Michael, a gorilla who lived with Koko for several years, also developed a broad vocabulary of signs, over 600, but did not become as proficient as Koko before his death in 2000. Michael's caregivers believe that he witnessed and remembered his mother's death at the hands of poachers, but was unable to express the event clearly. In the PBS Nature special Koko: Conversation with a Gorilla, a group of Michael's signs is interpreted to be an attempt to convey a description of his mother being shot as he watched. While it was intended that Koko and Michael might produce a baby gorilla and teach it to sign, the two saw each other as siblings and did not mate.

Another gorilla, named Ndume, was selected by Koko from a group of videotapes shown to her by Patterson, who played several tapes showing male western gorillas, in what may be described as an attempt at "video-dating." Despite these efforts, Koko and Ndume have also not mated. The Foundation is currently working to solve this, while Koko's biological clock still permits (possibly into her early forties).