Mona's cat, Ivan (16 months old), rescued last June Photo Mona Miller

There are 41 known species of cats, all descended from the same ancestor. A group of cats can be called a clowder, cludder or kindle. In medieval Britain, kittens were also called catlings. They are truly unique creatures, from physiologic to behavioral oddities. Cats have been worshipped as gods and are worthy of our respect and admiration, to which anyone who is a cat lover can attest!
Purring is one characteristic of cats that is a bit of a mystery and actually can occur in other animals as well. How cats purr has not yet been figured out, in part because there is no specific anatomic feature that seems responsible. Thus it is supposed that voice box vibrations are responsible. All cats purr at the same frequency range, of 25 Hertz, which is the same vibration frequency that is considered beneficial to healing. All cats can purr but members of the genus Panthera can purr only while exhaling (these are also the only cats who roar: lion, tiger, jaguar and leopard). Other animals that can also purr are raccoons, rabbits, squirrels, ring-tailed lemurs, guinea pigs in heat, and elephants and gorillas while eating.
While dogs have excelled at developing their sense of smell, cats have excellent hearing. A cat can hear 1.6 octaves above that of a human, and 1 octave above that of a dog. There are 62 individual muscles in the ear to allow for directional hearing, and each ear can move independently of the other. Compared to humans, cats see much better at night but worse during the day. They discriminate horizontal patterns well, but not vertical. While their color vision is poorer than humans, cats can see 25 times more shades of gray than can humans.
Cats are true carnivores and can subsist on meat protein and fat. Cats lack one of two proteins necessary for detecting sweetness as a taste. The other protein is present but the relevant taste buds are inactive. This is thought to be a mutation allowing cats to adapt fully to a carnivorous diet, ignoring plants that generally have a higher sugar content than meat.
Not all cats respond to the euphoric effects of catnip - about 20% of cats are missing the necessary gene.
Whiskers are important for navigation and sensation. Cats have four rows on each upper lip, and can move the upper two rows independently of the lower two rows. Whiskers may detect small shifts in air currents, allowing a cat to know it is near an object without actually seeing it. Whiskers give information about the size of a tunnel, and can form a basket shape around the cat's muzzle to precisely detect location of prey. One special note to my friends with well-fed cats: if your cat's body girth is wider than the length of whiskers, tip to tip, it's time to see your vet to discuss a diet!