Although there are times that a captive animal is in better conditions than they would be out in the wild, they are still stressed. Wild animals are not meant to be in captivity and this stresses them quite a bit. They start to go crazy and can become aggressive with other animals.
Most animals are use to being free and running wild, so captive animals must understand and know that they are not in their normal world, and with many humans watching them 24/7, they must be extremely stressed. Most animals in captivity never encounter a human in their lifetime so they must be stressed about what kind of creature this is and why does it have control over me.