1.) Those little rough spines on a cat's tongue are called "Papillae" and are used for grooming and to scrape meat off of bones.
2.) Cats usually shed their whiskers and claws about twice a year. I say the whiskers are lucky. :)
3.) Ailurophobia is the fear of cats. Many dictator types were terrified of cats: Napoleon Bonaparte, Julius Caesar, Adolph Hitler, Bennito Mussolini, etc. My theory is that they feared what they couldn't control, since cats aren't easy to boss around.
3.) Acetaminophen is fatally toxic to a cat.
4.) Cats hear better than humans or dogs. Quoted from Wikipedia: "Cats have excellent hearing and can detect an extremely broad range of frequencies. They can hear higher-pitched sounds than either dogs or humans, detecting frequencies from 55 Hertz up to 79 Kilohertz, a range of 10.5 octaves; while humans can only hear from 31 Hz up to 18 kHz, and dogs hear from 67 Hz to 44 kHz, which are both ranges of about 9 octaves"
5.) Cats don't have Circadian rhythms so not only are they active during both night and day, their body temperature does not vary. So they're always warm and cuddly.
6.) Cats walk like giraffes and camels in a "pacing gait" in which they move both legs on one side of the body before those of the other. However, when they break into a trot, they switch to a "diagonal gait" more common with other four legged mammals.
7.) Their canine teeth are perfectly spaced and designed to sever the spinal cord of their prey in one fatal bite. So when they leave a mouse or a bird alive, it is either to play or to educate a younger cat.
8.) A cat's kidneys are so high-functioning that they can survive on meat alone without water and are even able to drink seawater...though I don't think it'd be healthy.
9.) A female cat is known as a "queen" which sure beats being called a "bitch" or a "cow."
10.) Scientists say that cats lack the ability to taste sweetness, but I disagree. Many of my cats have had a sweet tooth.