Water has many uses in animals. For example, it is used to transport materials, removing waste from body, act as solvents and much more. So we might heard of doctors suggesting human to drink 6 to 8 cups of water each day, or else we may suffer form dehydration.
However, if animals don't take in food for a short time, they wouldn't die immediately. It is because inside animal body there is food storage, of carbohydrates (glucose) and fat. The body will break down these food store.
