Koko, beloved gorilla that mastered sign language, dies

The story of Koko the Gorilla: "Koko" was a western lowland gorilla born in captivity at the San Francisco Zoo on July 4, 1971, and quickly became a worldwide star due to her unique personality and high intelligence. As a baby, she caught the attention of Stanford University grad student Francine “Penny” Patterson, an animal psychologist who started teaching Koko sign language. News media covered Koko’s language skills, and the gorilla became a celebrity. Over the years, Koko learned to understa