Cats always land on their feet

...would be an excellent name for a band.

Evening, masukomi! One must handpick the specimen for perfect ripeness and just the right level of corpulent bloat. Just noding what I know. Similar applies to the cat.¹

Morning, apirkle! I assume the duck business involves the illusion that the echoes are the duck(s) continuing to quack, ¿verdad? Which brings us to the pussy. Quoth the Raven: ("Ruling Passions", New Scientist Feature, 3rd April 1999, Roger Lewin)

A MOUSE FALLS DOWN A MINE SHAFT, one thousand metres deep. Provided the ground at the bottom is fairly soft, it gets a slight shock and scurries away. A rat falling down the same shaft is killed, a man is smashed to pieces, and a horse splashes. The message is simple: in biology, size matters. Big time.

So I would have thought it moot as to whether the cat actually lands on its feet or not, and that until I tried I should never know.² Fortuitously, this matter of immeasurable philosophical import was discussed in the rec.skydiving archives (July 1996, "Do Cats Bounce?") and The Straight Dope Archives (19th July 1996, "Do cats always land unharmed on their feet, no matter how far they fall?"; 30th August 1996, "Why you shouldn't throw cats out of planes (cont'd)"³).⁴
     As the cat falls, it tenses and attempts to twist its body such that its feet kiss the earth first. Unless said kitty falls on unkind territory and perforates itself, falls from 2-3 stories up are generally walked away from. Higher swan dives allow for correct positioning of the legs but the cat unfortunately tends to remain tense until terminal velocity is reached (~100kph, after ca. 5 stories). Hence the 'flying squirrel' contention, in which the feline thereafter spread-eagles and lands on its belly, minimising injuries and increasing drag. This holds with a 1987 study from the Journal of the American Veterinary Medical Association which found injuries increasing as the level of departure does, up to 7 floors above ground, and decreasing beyond this demarcation.
     The quibble with jumping to such a conclusion, as so astutely highlighted by His Imperial Lordship, The Most Holy Cecil Adams' apt pupils, is that the spam-kitty cases get taken to the dumpster, not the veterinary hospital (and such is noted in a similar study on tenement-diving dogs). Severity of injury also varies, with alightment options likely to play an important role, along with factors such as the age, obesity and general heath of the individual. Sugar-gliding may explain why some cats survive, but it sure doesn't save 'em all.

PS Who among you would not pay good money to see the horse?

1. Lotsa things bounce; they just gotta relax and enjoy the ride. Trouble is, most people I knew were tightasses who wouldn't have known a good time if it hit 'em. Which it did. Hard.
2. Perhaps if one glued a cape to the subject's back and subjected it to some soothing hypnotic suggestion? ...if you want it, you got it, you just got to be-lieve...believe in yourself, yeah... Now if only I hadn't immolated, traumatised and variously frazzled the neighbourhood felidae: all I've got left are puppies, desgraciadamente. "Hey, Bob. Bob! BOB!!"..."When's the new shipment of kittens arriving?"........"You what?!".."You lobbed them off the ROOF? Dammit, they was gonna be my LUNCH."
3. This person's curiosity failed to kill this cat. But the chicken wasn't so lucky; apparently, it made a credible flight-is-not-in-my-specifications-but-I'm-darn-tootin'-going-to-try impression before transmogrifying into pudding. "Damn you, Mama! I never asked to be born a chicken!"
4. This is what we use the 'Net for?!? *sigh* "Give the people a death ray, they'll use it to make toast..."

No mammals were harmed in the writing of this node. Which is strictly true. After will be another story. Hehehe. TWAJS.

Actually, the only way to ensure that your cat does not land on its feet is to drop it from a very small distance. Cats are very good at flipping around to get their feet under them when dropped. In my experience, dropping a cat (upside down) from a distance of about 12 inches off the ground will be enough for the cat to rotate 180° before hitting the ground. If you were to drop a cat from say, 1000 ft, it would flip around until it was falling feet first and then continue to fall the next 999 feet in this position.

Cats can survive falls from very high places (there is record of one cat who fell from 32 floors up and survived with only minor injuries). Interestingly enough, past a certain point, the chances of the cat getting seriously injured actually decrease. This is related to the concept of "terminal velocity":

v_t = [(2mg)/(CρA)] ^½

v_t represents the terminal velocity.
mg is the mass of the falling object times the earth's gravitational pull (g = 9.81 N*M/s²).
C is the drag coefficient (a variable related to air resistance)
ρ is the air density
A is the effective cross-sectional area that will be experiencing the resistance from the air.

Once an object falling through vertical space toward the earth reaches a certain speed, it will cease to accelerate, and will continue falling at this constant rate. A falling cat, sensing the fact that it is accelerating toward the earth tucks in its head and bends its spine in an upside down "u" shape. Once our feline friend reaches its terminal velocity, it will cease to accelerate and will begin to relax, stretching out its legs, neck and spine into a more horizontal position. This action significantly increases A the effective cross sectional area, and the cat slows until it reaches a new, lesser terminal velocity. As our feline friend nears the ground, she once again pulls herself into her instinctive landing posision in anticipation of the impact.

The reduction in speed resulting from the cat relaxing and spreading out is enough to actually improve her chances of surviving the incident.