Do you think it could be sexual frustration(if that's possible for a tort). Is the animal instinct kicking in to want a female. I often thought this when we sometimes hear people say there lone my male Tortoise was humping a rock a shoe or a teddy. Does this not prove that it is instinctive to want to mate even though the male may never have seen a female. In Yvonnes case it wasn't a rock a shoe or a teddy, it was another male Tortoise.