Lizards are in solitary confinement

What is it about humans that makes us need human contact? It is literally a punishment for us to be left alone. It's called solitary confinement and it drives people crazy. But honestly why is it that we feel that we NEED other human contact to stay sane? Animals can go days without contact. Think about it, we put lizards or snails or ginny pigs or snakes or fish in a tank. We don't play with them. We don't talk to them. We treat them as we do the prisoners in solitary confinement and yet you don't see a lizard hitting it's head off the side of its tank desperately trying to kill itself from insanity. I guess it just amazes me that with our intelligence also comes this need for compassion and contact. I think that is what really sets us apart from nature, our need to be together.