Inside of a Dog -- Young Readers Edition FROM THE DOG''S POINT OF NOSE This morning I am woken up by Pump coming over to the bed and sniffing at me. Her nose is millimeters from my face, her whiskers grazing my lips. She suddenly sneezes explosively, an exclamation point on her greeting. I open my eyes and she is gazing at me, smiling, panting a hello. Go look at a dog. Go on, look--maybe at one lying near you right now, curled around his folded legs on a dog bed, or sprawled on his side on the floor. Take a good look. And now forget everything you know about this or any other dog.

Okay, I admit it--you can''t really forget all that you know. I don''t expect you to forget your dog''s name or his favorite food. But humor me and try. We are going to be looking at dogs through the lens of science, and science asks us to set aside what we think we already know and focus instead on what we can prove. It will turn out that some of what we thought all along about our dogs is true, and other things that appear obvious are more doubtful than anyone knew. And when we try looking from a new point of view--from the point of view of dogs themselves--new ideas may arise in our minds. So the best way to begin understanding dogs is by forgetting what we think we already know. The first thing to do is to stop thinking of your dog as if he is a human being.

It''s easy to make this mistake. We think about our dogs as if they are people, because being people is something that we easily understand. Of course, we say, dogs love and long for things; of course they dream and think. We believe dogs know and understand us, feel bored, get jealous, and get depressed. We believe our dogs do all these things because we do all these things. But we''ll come to a better understanding of dogs if we start with what dogs--not people--can actually feel, know, and understand. We understand human experiences the best. So it''s simplest for us to explain our dogs by imagining that their experiences are just like ours.

If a person''s eyes look mournful and she sighs loudly, we can figure out that she is sad, maybe even depressed. If your dog does the same thing, is it safe to say that he is sad? Depressed? Sometimes we''re right when we assume that dogs have feelings and reactions that match ours. Maybe our dogs really are depressed. Maybe sometimes they''re also jealous, curious, or extremely interested in having a peanut butter sandwich for lunch. But maybe they''re not. If we see an animal''s mouth turn up at the corners, we might think that the animal is happy. But a dolphin isn''t happy just because its mouth turns up--its mouth is made that way. A chimpanzee who shows his teeth in a grin is actually making a sign of fear and submission.

He''s about as far from happy as a chimpanzee gets. A human who raises her eyebrows is usually surprised. A capuchin monkey who does the same thing is not surprised--he''s signaling to nearby monkeys that he is friendly. A baboon who raises his eyebrows, however, is making a deliberate threat. (So be careful when raising your eyebrows at a monkey.) If we think only in terms of what humans want or do or like, we can end up missing or ignoring things animals do when they are simply being animals. TAKE MY RAINCOAT, PLEASE For instance, many dog owners have noticed that their dogs resist going outside when it''s raining. From this observation, they come to a conclusion: My dog does not like rain.

So the owner buys the dog a raincoat. My dog does not like rain. What does this mean? Does it mean that the dog dislikes getting rain on his body? It seems likely. Most humans, after all, do not like getting wet in the rain. But does that make the same thing true for dogs? We can look at the dog himself for evidence. The dog can''t speak up to say how he feels about the rain, so we must look at what the dog does. Is the dog excited and wagging when you get the raincoat out? This seems to suggest that the conclusion is true--the dog does not like rain and appreciates the raincoat because it keeps the rain off his fur. But there''s another possible explanation for this behavior: Maybe the dog is simply excited because he knows the raincoat means that he is (finally!) going for a walk.

More evidence is needed. Does the dog flee from the raincoat? Curl his tail under his body and duck his head? This suggests that the conclusion is not true: The dog doesn''t like the raincoat. What about how the dog behaves when his fur is actually wet with rain? Does he look bedraggled? Does he shake the water off excitedly? What does this mean? It''s hard to be sure. The dog''s behavior is not giving us a clear answer here. Does he mind the rain or doesn''t he? Does he need a raincoat or not? We need some more clues, so we could take a look at some animals closely related to dogs--wolves. Both dogs and wolves, obviously, have their own coats on all the time. One coat is enough; when it rains, wolves may seek shelter, but they don''t try to cover up with, say, leaves or branches. This suggests that dogs, too--except those with little or no fur--do not need an extra coat to protect them from the rain.

And a raincoat is something more than protection from falling water. A raincoat is a covering. It feels snug on your body. It presses on the back, chest, and sometimes the head of a dog who is wearing it. There are times when wolves get pressed upon the back or the head--when they are being scolded or "dominated" by another wolf. A "dominant" animal is one who has authority over another, "submissive," animal. A dominant wolf is usually older, stronger, and larger than a submissive wolf. Sometimes, a wolf who is trying to show his dominance will pin another wolf by the snout, or actually stand over the other wolf.

The wolf underneath will feel the pressure of the wolf''s body on top of him. The pressure of a raincoat on a dog''s back might feel similar. For a person, wearing a raincoat feels like being protected from water in the air. For a dog, wearing a raincoat might feel like being told that another, stronger animal is nearby. Is this the best interpretation of the dog''s behavior? Looking at the evidence will tell us. Most dogs, when they are getting put into a raincoat, freeze in place. (You might see the same behavior when a dog who is getting a bath stops struggling when his fur gets heavy with water or a heavy towel is placed over him.) This is what a submissive wolf does--hold still to show he accepts the other animal''s authority.

Ultimately, we can correctly conclude that a dog wearing a coat may go out peaceably into the rain, but it is not because he hates the rain or he likes the raincoat. It is because the coat makes him feel that someone else is in control. If we think about what human beings are like--we don''t like being wet and we want to protect our bodies from water--we''ll come to the wrong conclusion about dogs and raincoats. If we look at what dogs (and their close relatives, wolves) actually do, then we''ll come to a conclusion that is more likely to be true. AN ANIMAL''S WORLD AND HIS UMWELT In most cases, it is simple to start thinking of the dog as a dog and not as a small, furry human. All you have to do is to ask the dog what he wants. Then you must learn to translate his answer. The first tool you''ll need in getting that answer is this: understanding the point of view of the dog.

Each dog--each animal--has a point of view. Even more, each animal has its own world. It is a world made up of all the things the animals can see, smell, hear, or sense in some other way. It is a world made up of all the things that matter to the animal, that could help it or harm it, that are worth its notice or important for its life. One scientist coined a word for it: umwelt, or "self-world." (You say it OOM-velt.) A creature''s umwelt is made up of all the things that matter to that creature--all the things it notices or needs, can eat or sleep on or climb or fight with or run away from. For example, consider the tick.

You probably haven''t thought much about them. Maybe you''ve found one or two of these pests on your dog. It would be surprising if you had taken the time to consider what the world of a tick is like. But take that time now. Soon after hatching, a young tick climbs to a high perch--say, a blade of grass. Here''s where things get interesting. Of all the sights, sounds, and smells in the world, the adult tick is waiting for just one. It is not looking around; ticks are blind.

Sounds don''t interest it. Only one thing will get a reaction from that tick: a whiff of butyric acid, a chemical given off by all warm-blooded creatures (like us--and dogs). We can sometimes smell it in sweat. The tick might wait for that smell for a day, a month, or even up to a dozen years. Once it smells that precise odor, it drops off its perch. The tick''s body is sensitive to warmth, and now it begins searching for a source of warmth and scurrying toward it. If the tick is lucky, it will reach the warm, sweaty being it has sensed nearby, climb aboard, and drink a meal of blood. After eating once, it drops off, lays eggs, and dies.

The point of all this is that the tick''s world, its umwelt, is differe.