Donald Rehrig, age 13, of Allentown,, Penna., for his question:

Can an owl see in total darkness?

Light enters an eye through the pupil, It carries with it the colors and shadings of the view. The image of the view falls upon a screen in back of the eye, Sensitive and complex nerves send. along this information to the brain, This is true of your eyes., cats' eyes and owls' eyes, In every case light is necessary to‑ show up the view‑and carry‑‑‑it to the eye,

This means that no eye can see in total darkness, The owl is as blind on a pitch black night as you or I. However‑, some‑ creatures have eyes that are better suited than others for night work, The solemn old owl can see a lot better in the dusk or a dim.light than we can,

The pupil of any eye is surrounded by muscle. In brilliant light the muscle contracts, Much of the glaring light is shut off from the delicate inner eyes since the contracting muscle makes the pup‑i1, smaller. In a dim light the muscle relaxes, The pupil opens up# letting in more light, The owl can open up the pupils of his eyes very wide, This is how he manages to catch so much light and see so well in the dusk.

Many people think the owl has slit pupils, like a cat's. Actually his pupils are round as pennies.  Cat’s eyes are able to see in bright light and dim light. Miss .Puss can close her pupils so that only a pinpoint of light gets through daylights does not.dazzle her, She can open those slit pupils wide to see well in the dusk.

The‑owl can close his round pupils just so far. Bright light dazzles him, He can't shut much of it out, So he hunts at night. He very sensibly dozes away the day in a shady tree. If you walk past him, he may open just one eye and then go back to  sleep.

Cats and owls eyes both, however, shine in the dusk. This eyeshine is a trick to gain a double dose of light. It is a trick with mirrors. The mirrors are layers of special reflecting cells in back of the eyes. The light carrying the image passes into the eyes strikes the little mirrors and bounces right back, Mr. Eyeshine gets a double exposure of the of the view. The shady patches are just twice as dark„

Eyeshine helps the hunter’s night vision. But it sometimes gives him away to his prey. A mouse has Very poor vision. But sometimes he sees the owls bright eyeshine in time to lash for shelter. Then the owl swoops on silent,, downy wins too late for dinner.

On a pitch black night however, the owl and the mouse do not glimpse each other, There is no light to carry the view to the owls big round eyes. There is no light to reflect from his eyes to make eyeshine..