My favorite animals are bears I've just discovered awesome place where volunteers help bears (and not only!) which can't return to wildlife: https://www.facebook.com/orphanedwildlife/ (link to the facebook, cause their website got security problems)
If you think that zoo's are bad than you should watch how they treat animals in slaughterhouses. Compared to that animals in zoo's are in heaven.
Though I agree that zoo's are morally dubious. I do not often go to zoo's anyway but now that I think about it I might stop going based on ethical reasons. Is it really right to lock animals in small cages for some peoples entertainment and other peoples wealth? Do I want to support locking animals up for the sake of entertainment and making money off of it? I would probably say no to both questions. So why have I been going to the zoo all those times? I guess I never thought about it like this.