As Cam seemed incapable of letting his photo be taken without sticking out his tongue, we took one intentionally. That seemed to help, as he didn't do it again the rest of the day.
Joanna looks surprised because, in the twilight of the San Angel Inn, she couldn't quite make out that I was readying the camera. I think that in this photo she looks rather like one of those rare jungle animals photographed with a motion-activated camera.