Wildlife recreation places in Texas?

I live in Houston and am wondering what there is to do around here that's fun and has to do with wildlife. We have the zoo and aquarium, and I know San Antonio has a Sea World - what else is there? I'm hoping for some kind of wild animal park or refuge or something. I looked up wild horses, but I found out that the BLM doesn't have any official refuges in Texas. Any fun ideas would be appreciated!