When a baby chimpanzee or gorilla dies, the mother will carry the body around for several days before it may finally be able to move on without it; this behavior has been observed in other primates, as well. Jane Goodall has described chimpanzees as exhibiting mournful behavior toward the loss of a group member with silence and by showing more attention to it. And they will often continue grooming it and stay close to the carcass until the group must move on without it. Another notable example is Koko, a gorilla who was taught sign language, who expressed sadness and even described sadness about the death of her pet cat, All Ball.