There are also many kinds of animals. You can use dinosaurs, woolly mammoths, sea creatures, and all kinds of animals in this game. You also unlock more as you progress through each zoo.
A different aspect is all of the terrain of the animals. They all have different needs, so you have to put grass in some exhibits, water in another, or sand in another. This makes the game a little challenging to make the animals happy with their exhibits. It also adds more realism.
Lastly, what is fun about this game too, is you do not have limits. There have been many times I put the tiger in the aquarium, or let the T-Rex run free causing havoc. Sometimes when you are tired of being serious, you can always try weird things.