Do animals grieve ?

Do animals feel grief at the loss of their offspring ? I think that they do and there have been many instances of what appears to be grieving when their baby dies. The story of a killer whale off the coast of Vancouver Island carrying the body of her baby for 16 days is a heart rending one that clearly is about loss. It may not be the same as our grief and mourning but still is a sense of loss that the animal is exhibiting without a doubt. Other animals such as elephants have been documented clearly in grief mourning their dead ones, hovering around body nuzzling it and touching gently obviously aware of death. To think that we are the only species capable of grief is impossible to accept.