Escaping a Howl
If you make a flat straight line up to the grass with the ladder block and then climb the ladder you made you will escape.
This can be achieved by making a water fall by placing water blocks on top of each other and then entering it so you float up.
Use the following trick to get hot water.
1) Make a small room (it should be atleast 4 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.
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.