Koko became famous in the 1980s when her handlers at the Gorilla Foundation near San Francisco claimed she could communicate with humans through sign language. Koko reputedly knew more than 1,000 signs, which came in handy when she announced to researcher Francine Patterson that she wanted a kitten for Christmas. Patterson first tried a stuffed cat, but that didn't work. Koko wanted the real thing. So in 1984, Koko was presented with a kitten, which she named "All Ball," and began raising her as if she were a baby gorilla.
But a few months later the kitten escaped and was hit by a car and killed. Patterson reported that Koko repeatedly signed the words "bad, sad, bad," and "frown, cry, frown, sad," and could be heard making a sound similar to a human weeping.
In his recent book on signs of morality among chimps and the great apes, biologist Frans de Waal described the death of Oortje, "a happy character, playful and gentle with flapping ears. One winter the chimp started coughing, and an adult female was seen staring into Oortje's eyes.
"Without any apparent reason, this female burst out screaming in a hysterical voice while hitting herself with spasmodic arm movements, as frustrated chimps often do," de Waal wrote. "The female seemed profoundly upset about something she had detected in Oortje's eyes."
A female chimp in another hall that could not see what was going on, began screaming similarly. There were 25 chimps in the area, though most could not see Oortje, and they grew totally silent. Moments later, Oortje died.
What was going on there? It's hard to dismiss it as anything but anticipation, followed by grief, over the death of a friend.
It sounds all too human.