Untitled Document
 Is
there a link between eye size and
speed? Surprisingly, the answer is yes! U.S. researchers at the University
of Texas found that the fastest runners in the animal kingdom have some
of the biggest eyes for their body sizes. This is because the bigger
the eyes, the better the eyesight, which is beneficial when moving quickly.
“If you can think of mammals that are fast like
a cheetah or horse, you can
almost guarantee they’ve got really
big eyes,” said Chris Kirk, who led the study. “This gives them better
vision to avoid colliding with obstacles in their environment when they’re
moving very quickly.”
To determine which factors influence eye size, the researchers
collected measurements of eye size,
body size, and running speed in 50 mammals. They found that 89 percent
of the variation in eye size among
these mammals was due to body mass and maximum running speed. “One
thing that is always going to influence eye size is body size,” Kirk
said. “An elephant is always going to have bigger eyes than a mouse.”
 But even
after adjusting for body size,
the researchers found a significant effect of running speed on
eye size. “When you combine maximum running speed
and body mass as your two variables, influencing how
big an eye is, they can explain almost all of the differences
observed between species,” Kirk explained.
However, this is not true for humans. Although we have large eyes,
compared to those of fast
runners - like wolves - our maximum running speeds are significantly
slower than other mammals. Researchers concluded that in the case
of humans, fast running was not the selective factor that led
to the evolution of our large eyes. |
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