The growls are softer now, when they come, and there is more play, tail wagging. Sam grooms Ringo’s neck and chest, his teeth biting softly on him the way I’ve seen monkeys do. Ringo rolls on his back, belly exposed, sometimes biting Sam back.

The playing and the biting is causing more episodes of what we’ve been calling Sam’s “itchiness.” He’ll shake his head and his back leg will cramp up like he wants to scratch something but isn’t sure what or where. No one can explain it, not our vet, not the specialist, other than maybe it’s some kind of nerve damage in his jaw. None of them have ever seem anything like it. It doesn’t happen all the time or last that long, and seems instigated by excitement, and he doesn’t seem like he’s in pain or suffering. And yet, for us it’s hard to watch. It’s tempting to interrupt, to stop the playing, to keep them from it, but what is a life without play?