My adventure to Bristol Zoo

So last Monday (20/10/14) I went to Bristol Zoo to get some photos on how animals are perceived in the zoo. I got some interesting shots and shocked myself, some animals look so sad! I usually see animals as an interesting thing behind glass but then I look into their eyes and see their raw emotions underneath. Here is a small collection of my zoo photos, most of them are how people observe animals, the other photos are taken from what I feel could be the animals point of view.
What do you guys think?? Can animals live a fulfilling life in a zoo??