Elephants Mourning

Just how aware are these elephants? Some scientists think they may cry when sad, just like you and me. In this clip we see elephants coming upon the bones of the matriarch of their clan.

We see them interact with their find and hear a voiceover explaining their actions. How is this similar to the way humans mourn? How is it different? Is there some special significance to the way the elephants touch the bones with their hind feet?