We went to Ouwehand's zoo yesterday. Lousy weather for photography, solid overcast all the time.
This picture says it all for zoos. On one hand, live goes on, this mother is suckling her young. On the other hand, animals look out of place in an artificial environment as you can see by the background here.
I was by no means the only one carrying a DSLR, spotted quite a few of them. I was the only one using a monopod and not using the pop-up flash for everything.