As I type, my orange cat is sprawled across my desk. He stays as long as I scratch his chin and hops down when I stop. We have a family sort of relationship.
I understand him about as well as I understand my human family and I think of him as a small furry person. He lives in my home, uses the furniture and dishes and even has his own bathroom.
He probably enjoys the house more than I do, since he's always home. (He doesn't drive.) Back when we had a yard, he came and went as he pleased, coming to the door when he heard the call, "Here, kitty kitty kitty kitty kitty". (How do cats know what this means?!?)
It seems that cats, dogs and people go back a long long ways together and live together almost everywhere.
So why do we want to bring snakes, birds, ferrets, chinchillas and iguanas into our homes?
Maybe it's because we don't think of cats and dogs as animals. They aren't part of nature any more than we are - they have first and last names, talk and complain, eat food from the store, go to the doctor, wear clothes, have jobs and watch TV.
All of us are thoroughly domesticated.
Maybe keeping an iguana is a little like hiking in the mountains or kayaking down a river. An attempt to connect with the universe outside our safe, predictable, but boring domestic boundary and experience wildness. Then, again maybe not - having just watched Lizard greets man like dog I'm not so sure.....