Face Forward: What Type of Vision do Animals Have if Their Eyes Face Forward?

Problem: What type of vision do animals have if their eyes face forward?

Materials

• 2 sheets of notebook paper

• Cellophane tape

Procedure

1. Roll each sheet of paper into a 1-inch (2.5 cm) tube. Fasten the edge of the paper with cellophane tape.
2. Hold the tubes to your eyes as you would a pair of binoculars.
3. Keep both of your eyes open.
4. While looking through both tubes, slowly move the far ends of the tubes together until you see one clear image of the object being viewed.
5. Close your left eye, and make note of what your right eye sees through the tube.
6. Close your right eye, and make note of what your left eye sees through the tube.

Results

Each eye does not see exactly the same thing. The right eye views more of the right side of the object, and the left eye views more of the left side of the object.

Why?

The position of the eyes is very important. An animal that hunts for its food has its eyes facing forward on the front of its head like your own eyes. In this position, objects are viewed from two different angles. The two images are projected on the back portion of the eye (the retina) where they overlap. The overlapping images are interpreted by the brain as one clear, three-dimensional picture. The ability to combine images viewed by two eyes is called binocular vision.

Show Time!

1. A chameleon's eyes face forward, but the eyes can move independently of each other when searching for food. What might the world look like through the roving eyes of a chameleon? Move the far ends of the tubes in different directions—up and down, left and right. Observe and record what you see. You should know that when this animal prepares to take aim with its tongue to capture its prey, the eyes face forward, giving the animal good distance judgment.
2. How does binocular vision produce a three-dimensional view? Discover how the overlapping of two images produces a three-dimensional picture by holding this book so that the tip of your nose touches the dot in the diagram. Keep both eyes open. Look straight forward as you slowly turn the book in a counterclockwise direction and watch the car travel up the path. Design other diagrams and use them as part of a project display. Make sample copies for project observers to turn so that they can see the objects move.
3. How good is your peripheral vision (your side view vision)? Your eyes, like those of other animals with eyes facing forward, have about a 180-degree angle of vision. Test your peripheral vision by standing in the center of a circle. Ask a helper to start from a point on the circle behind you and to slowly walk around the circle. Continue to look forward, not moving your eyes to the right or left. A mark is to be made on the circle when you first see your helper and again when he or she moves out of view on the opposite side. Test the angle of peripheral vision of other people. Photographs taken during this experiment can be used as part of your project display.

Check it Out!

Horses have eyes so placed that they can see all around their heads. The eyes of owls remain stationary, but their heads rotate 180 degrees, so they, too, can view the entire world around them. It is difficult to sneak up on an animal that sees from all angles. Discover more about the position of animal eyes and how this position affects an animal's life.

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From this Book:

Janice VanCleave's Animals
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