"The fact that she chose to be near Thomas and clean his teeth over receiving abundant and delicious food from the caregivers indicates that she was motivated to stay with him," van Leeuwen told The Dodo.
While it's hard to generalize about chimpanzees' behavior from a single case study, van Leeuwen said, Noel's actions are certainly significant. Not only can it help us understand chimp emotion, behavior and social interactions, but it may also help us figure out the evolutionary origins of human funeral rites.
Of course, chimpanzees aren't the only animals who appear to mourn their dead. Elephants have been known to remain with the dead bodies of their loved ones for hours. Dogs have mourned the loss of their human companions by following funeral processions or lying on graves. Recently, a horse grieved for his dead owner by resting his head on the owner's coffin.