Common Squirrel Monkey (Saimiri sciureus) hand on cage bars
I have very mixed feelings about zoos. I don't presume that the individual animals in zoos are miserable or abused or otherwise mistreated - while obviously there are cases where that is true, I've seen enough behind the scenes of my local zoos & animal shelters to believe they very much do care for & respect the animals.
Some of their animals are less happy than others - it's difficult being a wolf with a genetic impulse to roam across many square kilometres, stuck in a comparatively tiny acreage - but many, including these Squirrel Monkeys, seem quite content & entertained with their existence there. And as I've commented previously, Oakland Zoo's new expansion - where they now house most of their larger mammals & birds - has impressively large & well-equipped enclosures [for a zoo].
In the end I guess I think zoos currently fulfill a need for education that does far more good than harm - e.g. imbuing children & adults alike with appreciation for the amazing animals all around us, which I hope winds up saving whole species that would otherwise be lost to greed & apathy.
Still, it's hard to see moments like in this photograph and not feel sad, too.