I don't know if it is just the shape of their face, but this wild pig looked sad and lonely, like he really knew he was caught up in a zoo, never to see his homeland or family again. Their eyes communicated a higher level of intelligence than many of the other animals - don't know if that's true or not.
Okay... for curiosity' sake, I just looked it up. Yep, pigs are among the most intelligent animals, I guess. So perhaps this guy really is sad. Interestingly, the younger one (on the right) only moved at the exact moment the adult did. It must be some sort of training or emulation for safety sake.