Expert: Walter Hintz - 2/10/2009

Question
Hi there! While I was watching Animal Planet, it hit me that a lot of times the narrator will talk about how certain animals have X many times better sight than humans. However, they never seem to tell how they know this information. I tried to research these topics, but any in-depth explanations are too scientifically worded for a non-science person like me to understand. But at least I know that scientists didn't find out their information by asking an animal to read an eye chart!
So, I would like to understand how researchers measure the sharpness of an animals's eyesight, how well they see at night, and how well they see in color. Thanks very much in advance!

Answer
  Hi Ted
How and what  animals see can be determined by studying the behavior and their place in a food web.  We know that predatory birds have acute eyesight because they feed of small mammals. A hawk can spot a small mouse from a great distance away.
WE now about color vision by looking for color receptors in the retina.