Why do people say that cats have nine lives?
[ 2006-07-24 11:57 ]
人們常說貓有九命，果真如此嗎？一只貓從很高的樓上掉下來，多半都能安然無恙，讓你不得不相信它真的有那么多命。那么，事實(shí)果真如此嗎？讓我們一起來探索一下吧！
 Some people believe in the superstition that cats have nine
lives, because cats can survive falls from high places with few, if any
injuries. This gives the appearance that the cats return to life after
sustaining a fatal accident. Granted, they may sustain minor injuries, such as
bloody noses, cracked teeth, or a few broken ribs, but they live to
recover.
The ability of the cat to survive these accidents that would
kill humans or other animals is not due to multiple lives, but to several
advantages they possess. Their small size and low body weight soften the impact
as they make contact with the ground after falling from great heights.
The highly developed inner ears of cats equip them with an unusually
keen sense of balance, which is critical to their landing on their feet. This
sense of balance allows a cat falling upside down to right himself by rapidly
determining his position, repositioning himself, and making any adjustments
necessary to ensure that he lands on all fours.
Since cats land on all
four paws, the impact from landing on the ground is absorbed by all four.
Additionally, cats bend their legs when they land, which cushions the impact by
spreading the impact, not only through bones that could easily break, but
through the joints and muscles as well.
Most are surprised to learn that
a cat stands a greater chance of survival if it falls from a higher place than
from a lower place. New York veterinarians gathered data from their
feline patients, which clearly
support this fact. Ten percent of their patients died after falling from 2-6
stories, while only five percent of the fatalities occurred when their patients
fell from 7-32 stories.
Laws of physics explain why these survival rates vary. All falling bodies,
regardless of their masses, accelerate by 22 miles per hour per second of their
falls. The falling object, after traveling a certain distance through the air
reaches a final speed, or "terminal
velocity," because the object's friction with the air slows the
fall. The smaller the object's mass, and the greater its area, the more it will
slow.
A cat falling from a higher floor, after it stops accelerating, spreads
its legs into an umbrella shape, which increases the area against which the air
must push and increases the friction, thus slowing the cat's fall. Through the
cats highly developed sense of balance, he buys more time to maneuver his body in preparation for landing on
all fours. A cat falling from a lower height does not have the opportunity to
increase its body's area, slow its fall, or position his body to land on all
four feet.
veterinarian: 獸醫(yī)
feline: 貓科動(dòng)物
velocity: 速度
maneuver: 控制
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