Tweets and treats.

Animals learn a lot like kids do--first you have to get their attention. "The key is learning what motivates the animal," says Dr. Jeff Proudfoot, of the Indianapolis Zoo.

It's fairly simple; when an animal does what the trainer wants--open its mouth--it gets what it wants. Usually that's food.

But you also have to teach the animal when to open up. Using a whistle helps the animal remember the treat and the tweet come together.

Usually the first step is to get the animal to focus its attention on something, called a "target." A whistle and a treat every time the animal looks at the target soon gets the message across.

Another reward and whistle comes when the mouth opens, and again when the animal keeps its mouth open for longer periods of time. Soon, the trainer need only blow the whistle to get the animal's cooperation for a dental exam.

Does your dentist wish it was so easy to treat you?