It has been documented on film many times that when elephants are traveling and come across the bones of a dead elephant, they will stop and gather around the bones. As they are there, they will gently begin to touch the bones with their trunks (usually the Alpha Female first) and gently caress the bones. They will spend hours around those bones doing such. And all of those there will do this, even the wee little elephants, who I suspect are simply parroting the actions of the grown ups, but this is how they learn.
They have never been documented doing this with any other bones from any other species. And recently, I saw a film clip where the bones had been spread apart by scavengers, and the grown ups gently picked up the bones and put them in a pile one with another..........it was both sad to watch and fascinating at the same time.