Human beings live every day with the understanding of our own mortality, but do animals have any concept of death? It's a question that has long intrigued scientists, fueled by reports of ants, for example, appearing to attend their own"funerals"; chimps gathering somberly around fallen comrades; or a mother whale who carried her dead baby with her for two weeks in an apparent show of grief. Philosopher Susana Monsó is a leading expert on animal cognition, behavior and ethics at the National Distance Education University (UNED) in Madrid, Spain.