Reading Comprehension • Saddleback Educational Publishing ©2002 100 3 Watson, Irvine, CA 92618•Phone (888)SDL-BACK•www.sdlback.com
Na m e : ___ _
Directions:Date:Read the questions below. Keep them in mind as you read the tale. Then go back
and answer them.When you read, try to imagine the picture the
author tried to paint for you.- Does an elephant live about 30 times longer than a small shrew? ___
- Does time pass more quickly for small mammals than large ones? ___
- From whose point of view do you learn this information? __
- What factor, other than metabolism, may affect the actual length of life of any animal?
______________________________________________________________________________________- Why might today’s humans generally outlive their projected metabolic lifespan?
______________________________________________________________________________________- After reading this article what is your perspective on the passage of time? ____
______________________________________________________________________________________It is natural for us, as humans, to think about things from a “human”
point of view. Take time, for example. Although time passes at the same
rate for all living things, the lifespan of any particular species varies
greatly. To us, a year is perhaps^1 ⁄ 70 of a lifetime. To an animal that lives
about 2 years, it is^1 ⁄ 2 of its life.
In general, large animals have longer lifespans that small ones. Does this
mean that small animals live “faster” than large ones? The rate of living, or
metabolism, can be measured by counting the number of times the heart beats and number of
breaths that are taken in a minute. A small shrew’s heart may beat 800 times a minute, and it
may take about 200 breaths. During the same minute, an elephant’s heart ticks 25 times,
and it takes just 6 breaths. The shrew’s metabolism is going about 30 times
faster than the elephant’s—thirty “shrew” days is equivalent to one
“elephant” day.
We cannot know if our mammal friends perceive the passage of time
differently than we do, but some scientists say that all mammals
have about 200 million breaths and 1000 million heartbeats in
them. What about us? According to that formula, for our size, we
should last about 30 years. In fact, before modern medicine and
other developments that have lengthened our lifespan, we did little
better than that.