Taken from http://en.wikipedia.org/wiki/All_Ball

All Ball was a pet cat of Koko, the famous gorilla living in Woodside, California, who is purported to communicate via sign language. Koko's relationship with All Ball was featured in the 1987 Children's book Koko's Kitten (Scholastic Press, ISBN 0-590-44425-5), which was written by Koko's trainer, Dr. Francine 'Penny' Patterson. In the book, Patterson reported that, in the summer of 1984, Koko asked her for a cat. Koko selected a gray male Manx from a litter of abandoned kittens and named him "All Ball." This breed is unusual in that it has no tail. Patterson wondered whether that influenced Koko's choice. Patterson wrote that Koko cared for the kitten as if it were a baby gorilla.
In December of that same year, All Ball escaped from Koko's cage and was hit and killed by a car. Later, Patterson claimed that when she signed to Koko that All Ball had gone, Koko signed “Bad, sad-bad” and “Frown cry-frown sad.” Patterson also reported later hearing Koko making a sound akin to human weeping. Patterson uses this to argue that non-human species can have human-like emotions.
In 1985, Koko was allowed to pick out two new kittens from a litter to be her companions. The animals she chose, later named "Lipstick" and "Smokey," were also Manxes like All Ball.