Pet Health Pictures Slideshow: Is My Cat Normal?

Sleeping all day, chasing shadows all night, getting high on mysterious herbs -- that may be delinquent behavior for a teenager, but it's run of the mill for a cat. Learn more about the peculiarities of feline protocol so you can sort harmless kitty quirks from cat behaviors that could spell trouble.

A cat rubbing her face on you is a sign of affection. Cats have glands on their cheeks and the corners of their mouths. When they rub up against your leg or other body part, they leave some of their scent on you. According to feline etiquette, that's a compliment.

You've politely told your little predator, "No, thanks." But your cat insists on showering you with gifts of dead mice, birds, or lizards. Bringing you dead animals is normal, but it's best to keep your cat inside. Prowling cats can have a devastating impact on ground-nesting birds. Instead, give your cat toys she can hunt for inside. It will give her an outlet for her predator behavior -- and keep wildlife safe.

You've watched your cat's painstaking grooming ritual. Why would he go to all that trouble keeping himself clean and then drink out of the toilet? No one is sure why cats do this. Toilet water may taste fresher than stagnant water because it's changed with each flush. Don't worry about it unless you keep chemical cleaners in the tank. And if it really bothers you, keep the lid down.

Eating small amounts of grass can be nutritious for cats. In larger quantities, it can have a laxative effect or cause vomiting. If your cat is drawn to eating greenery, take inventory of your houseplants. Many species are toxic to felines, such as aloe and philodendron, and Easter lilies, which are deadly.

In rare cases, cats are compelled to eat the inedible. For unknown reasons, wool is particularly appealing. Some suck on it. Some actually eat it. Some cats may even eat big holes out of sweaters. This behavior is considered compulsive and is most common in indoor-only cats. Talk to your vet about behavior modification. It may help to provide tasty alternatives, like catnip, grass, lettuce, or rawhide.

It may seem lazy, but sleeping or lounging around the whole day is a survival trait if you're a cat. As they evolved in the wild, felines developed a pattern for conserving energy. They hunt for a short period and spend the rest of the day sleeping. In house cats, the pattern is similar. A kitten will eat and play in brief bursts, but spend most of her time at rest.

Just like people, some cats are more "talkative" than others. They may meow and whine throughout the day. Asian breeds, particularly Siamese cats, are prone to vocalizing. As long as your cat doesn't seem anxious or in pain, being a chatterbox is no cause for alarm. However, a quiet cat that suddenly begins vocalizing should be examined. The change in behavior could signal a medical condition, such as hyperthyroidism.

Your new slacks may suffer a few snags, but your cat means well. When Tiger jumps on your lap to knead your legs, it means she's feeling relaxed, comfortable and secure. Kneading is learned very early in a cat's life. It's something most kittens do while nursing.

If your cat makes a habit of licking your fingers, there are several possible reasons. The first is that your cat simply likes the taste of your sweat or hand lotion. In some cases, licking can be a comforting behavior; it may be linked to nursing. If your cat licks you excessively and shows other signs of anxiety, check with your vet.

If a pinch of catnip sends Fluffy into a state of bliss, you might wonder if your innocent furball is getting high. The answer is yes. Chemicals in catnip produce a response similar to intoxication. Because there's a genetic basis for it, some cats show an extreme attraction. Others show no reaction at all. In some cats, this naughty herb may even cause hallucinations. Catnip is not toxic to cats. However, eating large amounts can lead to vomiting or diarrhea. Catnip shouldn't be given to pregnant cats.

Like people, cats are vulnerable to allergies, sinus irritation, and upper respiratory infections. Symptoms may include sneezing and a runny nose. Sneezing in cats is most often caused by a viral infection picked up from being around other infected cats. Other causes of sneezing may include inhaled allergens, blades of grass, or even tumors. If sneezing continues for more than a few days, check with your vet.

Cats naturally tend to be active at night, when their superior vision lets them sneak up on prey. Most domesticated cats adjust their schedule to be active when people are awake, but this doesn't always happen. If your darling is a night owl, try providing an intense play session and a meal right before bedtime. The burst of activity should wear Dracula out, so you can both get a good night's sleep. But if your older cat suddenly stays awake all night, check with your vet: It might be a sign of hyperthyroidism.

Many cultures, such as the ancient Egyptians, have admired cats as divine beings. The fact that their eyes glow in the dark only adds to the mystique. As it turns out, there's a fairly mundane explanation for this phenomenon. Feline eyes have a layer of tissue called the tapetum lucidum, which reflects light back through the retina. It helps facilitate their exceptional night vision.