Scholarly Cat Critic Lands on His Feet
Having recently mentioned the reflex gyrational mechanism by which cats right themselves when falling, perhaps I owe my readers a more thorough examination of this phenomenon and its consequences.
Rod Casper has sent me an article from Nature magazine (April 14, 1988), by Jared M. Diamond, on the results of a study on falling animal bodies by W. O. Whitney and C. J. Mehlhoff as reported in the Journal of the American Veterinary Medicine Assn.
(Casper, by the way, is the one who sent me that clipping about a dog in Buenos Aires that fell from a 13-story window, hit a 75-year-old woman, killing both, and causing another woman to be killed by a bus and a man to drop dead of a heart attack.)
Happily, Whitney and Mehlhoff worked in an animal hospital in New York City, whose skyscrapers, open windows and hard pavements produced a data base of 132 cats that were killed or injured by falls of two or more stories, with a maximum of 32 stories and a mean of 5.5 stories (one story equaling 15 feet).
Excepting 17 cats whose owners could not afford veterinary treatment and had them euthanized, 90% (or 104 of 115) survived; 11 died, mostly of shock and thoracic injuries.
What Diamond found most remarkable in the results was that the incidence of injuries and death peaked in falls of about seven stories; cats falling from greater heights suffered less severe injuries and were more likely to survive.
One cat, for example, fell the maximum height of 32 stories, onto concrete, and “was released after two days in the hospital, having suffered nothing worse than a chipped tooth and mild pneumothorax.”
Human beings, on the other hand, rarely survive falls of more than six stories onto concrete. Higher falls are increasingly lethal. Death is caused most often by head injuries and bleeding from internal injuries.
The doctors found that injuries were affected by three sets of variables: the height of the fall determines the impact velocity; the softness of the landing surface affects the impact force, and five properties of the falling body are relevant, including its mass, shape, bone strength, cushion of fat, and use of muscles and joints to reduce impact force.
Large animals (including human beings) suffer greater injuries in falls than smaller ones, their less favorable area/mass ratio causing higher velocities.
Like all of us, cats have only one life each, not nine, but this popular misconception evidently comes from their frequent escapes from injury through the use of their remarkable gyroscopic system that enables them to turn in the air and point all four feet downward, thus dissipating the landing impact over all four limbs.
Falling adult human beings tend to tumble uncontrollably, landing usually on their two feet, next most often on their heads. Babies, because of their larger heads, fall on their heads, with their arms reflexively extended to break the fall.
After about 100 feet, cats reach a terminal velocity of about 60 m.p.h., adult humans about 120. The doctors theorize that when accelerating, cats may extend their limbs reflexively, but on reaching terminal velocity they may relax and extend their limbs more horizontally, like flying squirrels, thus reducing velocity and spreading the impact over a greater area of their bodies. This may explain why cats suffer less in falls of more than 100 feet.
Diamond, a professor of physiology at UCLA Medical School, says cats share advantages with other small animals of similar mass and shape, but their gyroscopic righting reflex and their limb flexing on landing are unique. Thus, small dogs that fall from buildings are more prone to serious injuries or death than cats.
Diamond theorizes that specific cat advantages have undoubtedly evolved through natural selection. “Most felid but few canid species are arboreal, so that millions of years of springing or falling from trees have favored those felids with the best vestibular systems. Thus, the nine lives of cats are a product of their evolutionary history.” (The vestibule is a portion of the inner ear that is involved in balance.)
I hope this study will not prompt anyone to drop a cat from a second-story window. Whatever the statistics, it doesn’t do them any good, and I have an idea that they don’t like it.
