Here's the thing though. As a travel photographer your job is to capture not just the animals - although they're an integral part of it - but the zoo itself.
Wildlife photographers can ignore any and all signs of human existence, although hopefully they don't try and tell the world that their captured beasties were photographed in the wild.
The travel photographer on the other hand is there to capture nice portraits of the animals, but perhaps more importantly the feeling of being at the zoo itself.
To do this we need to take a step back and have a bit of a think of how the zoo affects the visitor, how they interact with it. And when I say take a step back, I mean literally a step back.
So you need to show the cages. Now in some zoos I've visited the cages are horrible, concrete monstrosities with thick steel bars. At Singapore zoo they're much more animal friendly and enable more interaction between the viewers and viewees.
With the baboon enclosure here I took a couple of shots of the monkeys themselves - close up portraits of them involved in various shenanigans. But it wasn't working for me. It wasn't where the photo was. So I backed away from the glass to take in the whole scene and that's when it occured to me that the actual picture was the enclosure itself. The fact that you had big glass panels where you could get up nice and close to the animals, the fact that they stretched in a big semi-circle to give a really wide view, and the fact that that was how the people experienced the baboons - and vice versa.
So whereas I would love to spend a day photographing close-ups of animals, as a travel photographer we need to take a wider view of what we're there to photograph. We're trying to create an image of a zoo as a destination for people to interact with animals and get to know them a little better.