I think it depends on the animal and the enclosure. As a general rule, I do not agree with large mammals being kept in captivity (elephants, large apes, sea mammals, etc). They are just too intelligent and too big for captivity to do them justice. I find it particularly sad when I see dolphins and whales in captivity.... super intelligent animals that are used to having free reign of the open ocean confined to a glorified aquarium and coerced into doing tricks for our entertainment.
I do feel that smaller, less intelligent animals can lead a quality life in captivity.
Despite the negatives, I will say that zoos do alot to promote awareness about the plight of wildlife. Kids love the zoo... they don\'t necessarily grasp the fact that these animals are being held captive, they just like to check them out . This interaction fosters their interest in wildlife and may lead to them persuing a career in ecology or environmetal science and helping to preserve nature or making some kind of difference.
In short, yes, it sucks for the individual animals that are stuck in cages. However, these aniamls act as stewards of their species in a way and open peoples eyes to what they have to lose by not recycling that can or throwing that battery in the trash can. It\'s almost like they sacrifice themselves for the betterment of their species and nature in general.
If it was not for zoos, many people would not even have a clue these animals actually existed, and that would make it even harder to protect them and their environments.
I guess my opinion is that zoos are a necessary evil of conservation. I do sort of get depressed when I go, but my 18 month old son absolutely LOVES it. And, if it gets him excited about animals and conservation, then it is a good thing.