A gorilla who can speak sign language has appeared in a new video to raise awareness for climate change. Arguably the best known member of her species in the world, Koko is a female western lowland gorilla who over the last 44 years has shown just how similar humans are to our primate cousins. ... "Man Koko love, Earth Koko love. But man stupid," she said. "Fix Earth! Help Earth! Protect Earth."