Missing Friends
Bonedigger grew up with another big cat, Tony. The tiger cub had entered the sanctuary at the same time as Bonedigger, so they essentially grew up together.
But as it became apparent that the animals were getting too boisterous with each other, putting Bonedigger at risk from injury, John was forced to keep him in his own enclosure. And there he stayed until an uninvited guest found itself thrown into the ring.