Animals in Houston Zoo

During the previous visit to Houston we had bought the city pass which provided concessional entry to five major tourist attractions. It has been a long time since I visited a zoo so that made the decision for one of the attractions. The visit was well worth considering the exotic species that are on display. One thing I was not too impressed was that the Tiger had a very small cramped space, while species of Monkeys had relatively larger spaces. I wonder why this inequality, maybe the authorities are afraid of making the Tiger aggressive by giving it too much space to move around? I don't know...