Hints
Be careful deforming land too near your herds - they'll probably end up in the sea.
Don't overwhelm your population of herbivores with predators, unless you want to create a barren wasteland.
Plants and animals alike need water to survive, so make sure there's a decent flow from somewhere.
Hot water
Use the following trick to get hot water.
1. Make a small room (it should be at least four blocks long).
2. Put lava at the back of the room.
3. Put water in front of it (you will not see the lava).
4. Swim in the water and to the back of the room.
5. Your screen will flash red.