While I agree that many zoos promote research and conservation of animals. The sad fact is that within my children's lifetimes and certainly my grandchildren's lifetimes, many animals will exist only in zoos. As humanity's voracious appetite for land and resources continues to devour the natural habituates of many animals, the zoos or prisons, as C9Gal refers to them, will be their only existence.
There is a great truism, in my opinion, which states you can judge the character of a person by how they treat those whom can't hurt them. In this regard, I feel, we humans will have a lot to answer for to God. Let's face it, the research done in zoos is secondary to the arrogance of humans. Only humans will in imprison another species solely for their own selfish satisfaction. The fact is the animals in zoos are put on display for the enjoyment of the human audience. Gary Larson's Far Side cartoons showed this succinctly in his cartoons of humans looking out at the world beyond in alien zoos.
While I do not share C9Gals strong feelings against zoos, I recognize them and admire her for her stand. While, I think zoos are an evil necessity, I believe we should not fool ourselves to the Machiavellian and pecuniary nature of zoos. They make money for the owners by putting on display creatures who have no control over their own lives. They also do it as cheaply as possible.
I have visited over a dozen zoos in my lifetime. I found that in many, the large apes and cats are cooped up in small quarters and do not seem to be happy animals. Large cats that pace back and forth over and over or apes who seem to contemplate their own drool do not seem happy to me. These look to me to be the actions of neurotic animals. Then, I am not a zoologist so I could be wrong.
Just my two-bits.