This week, we're going to talk about cat body language again. But this time, we're going to focus more on what you, the human, can learn from the way your cat friend is expressing himself to you. Also, we want to let you know that we're taking a vacation next week, so our next column will appear on Monday, Sept. 6.

Sinéad: As you must know by now, a cat's vocal sounds represent only a tiny fraction of its communication. Even loudmouthed breeds like Siamese...

Siouxsie: ...or loudmouthed cats like our adopted brother Thomas...

Sinéad: ...communicate much more with their bodies and facial expressions than they do with their voices.

Siouxsie: In last week's column, we talked about signs of aggression and defensiveness in cats. We don't think humans see these expressions directed at them as much as they might see other, more subtle signs of cats' emotional states.

Sinéad: But let us remind you that if you do see a cat behaving aggressively, back off. Whether the cat is angry or scared, he will defend himself to the best of his ability, even to the extent of biting and deeply scratching humans who frighten him.

Siouxsie: In more ordinary interactions, though, the most obvious indicator of a cat's mood is the position of the tail.

Sinéad: That's right. We know of many cats who greet their humans at the door with their tails held straight up. That's a hangover from kittenhood, and it means the cat is happy to see you. When we were kittens, if we came running up to our kittymama with our tails up, she'd lick our little behinds and clean us up.

Siouxsie: Of course, we don't expect--or want--humans to touch our behinds! A raised tail is just our way of saying, "Hi! We're glad to see you!"

Sinéad: Sometimes we walk around with our tails sort of halfway between horizontal and vertical. Generally that means we're happy and content and we feel safe.

Siouxsie: If a cat holds his tail straight behind him, and maybe just a little lower, it means he's on the hunt. I usually do this when I'm about to play Chase with Sinéad, or when Mama gets the string out and I'm lying in wait for my opportunity to strike my unsuspecting prey.

Sinéad: A slight twitching at the very end of the tail means the cat is excited and stimulated.

Siouxsie: Sometimes we'll hold our tails up but the end will be bent or curved. Mama calls that our "question-mark tail," and she knows that means we're curious about something.

Sinéad: We cats will twitch our tails if we're getting annoyed, too. As we said last week, "wagging" does not mean happiness in cats.

Siouxsie: For example, sometimes when Mama pets me, I start getting overstimulated. The petting stops feeling good and starts to hurt or irritate me. When that happens, I start twitching my tail, and Mama knows it's time to stop petting for a little while and let me calm down.

Sinéad: Cats that are really annoyed will lash their entire tails from side to side.

Siouxsie: And, of course, if we're all fat-tailed, that means we got scared or upset.

Sinéad: Rubbing is a part of our repertoire, too. We cats have concentrated areas of scent glands on our heads, under our tails and between our paw pads. Our "happy cat" scents come from the glands in our heads, and our "agitated cat" scents come from our tail area.

Siouxsie: So when we rub a human with our head, it means "welcome home, we love you, we're glad you're here."

Sinéad: If we rub a human with our tail area, we're marking, but we're kind of anxious too. Maybe the human in question is a stranger to us and we're stressed to see someone we don't know.

Siouxsie: The claw-area scent is pretty neutral. When we scratch on our scratching post, or on a tree, or on your furniture, we're grooming our claws and making a mark that we were there.

Sinéad: We cats also use the position of our ears as body language. If our ears are forward and held high, it means we're calm but alert.

Siouxsie: If our ears are laid back flat against our heads, we're either very scared or very angry. Don't go near a cat whose ears are flat against his head. Just give him some space.

Sinéad: When we're really calm, our ears relax, too. In most cat breeds, the ears don't just flop down--we have cartilage that prevents that--but our ears may appear to be at "half staff." You'll see that when we're sleeping or when we're very comfortably situated in your lap.

Siouxsie: The position of our whiskers also conveys our emotions. When we're curious about something, our whiskers stick out forward in front of our faces. Our whiskers are a sense organ, after all, so we employ all our senses when something intrigues us.

Sinéad: Cats that can't see very well will often carry their whiskers sticking forward all the time. It makes sense, because a blind cat can bump things with her whiskers before she runs into them.

Siouxsie: Cats that are calm but awake will carry their whiskers sticking out sideways.

Sinéad: The whiskers of very relaxed and happy (or sleepy) cats will fold back closer to their faces.

Siouxsie: Of course, angry cats put their whiskers back, too, so rely on your judgment and common sense to tell you what other signals your cat is giving.

Sinéad: As Siouxsie said, whiskers are important sensory organs for cats. A cat that loses its whiskers, whether due to an accident or the ignorant or malicious act of human beings, will act very strange for a while until either the whiskers grow back or it gets used to living without them.

Siouxsie: Usually a whiskerless cat will stagger around and sway its head back and forth. There are nasty, mean people who think this is funny, but nice people think it's sad to see a cat so incapacitated.

Sinéad: The eyes of a cat can speak volumes. A cat with wide-open eyes is alert and intrigued. Combined with small pupils and eye movement, that means the cat is tracking an object of interest. Sometimes it's a mouse, sometimes it's a fun toy, and sometimes it could be a little six-legged snack.

Siouxsie: On the other hand, a cat with wide-open eyes and dilated pupils is scared or overstimulated by petting or other activities.

Sinéad: A relaxed and happy cat usually has her eyes half-closed. When I'm sitting on Mama's lap and she's petting me and I'm so happy I'm purring, usually my eyes are half-closed, too. I know I'm safe and I don't have to be on the lookout for danger.

Siouxsie: Any combination of these body language gestures can be used at any time. Of course, there are many more ways that cats communicate with their bodies, but these are the obvious ones that humans are more likely to notice.

Got a question? Need some advice? E-mail Sinéad and Siouxsie at advice@paws-and-effect.com. None of the advice in this column is meant to be a substitute for regular veterinary care.