What's in Your Periphery?

Objectives: Students will compare the vision of predators and herbivores with their own binocular vision.
Related Web-Activity: Forest Carnivores
Subjects: Biology, Physiology
ELRS: Science 1.2, 1.3
Size: Whole class to individual
Setting: Flat, sandy field or concrete basketball court
Duration: Twenty minutes
Materials: Chalk and four rocks per group of four

Background

Is your skull built like a carnivore's or an herbivore's?

The skulls shown are of a bobcat and deer (left to right). There are many obvious differences between these skulls. Each of their characteristics provides the animal with a strategy for survival.

Focus on the eye sockets for a moment. The primary difference in eyes among predator/prey species is the breadth of binocular and peripheral vision. Carnivores need good binocular vision so they can easily determine how far they are from their prey. Herbivores need good peripheral vision to see a swath of the landscape. Herbivores are always on the lookout for predators; keeping a good distance from approaching predators means survival.

Procedure

Gather your class outside on a large field of sand or basketball court. Break them up into groups of four and give each group four small rocks (or red and yellow flags as shown in the diagram at right) and a piece of chalk.

Have each student plot their binocular and peripheral vision on the pavement using chalk or using a stick in sand. Each member of a group should stand in the same location so they can compare their vision types. The student being testing is to be looking straight ahead at all times. A good way to keep students from twisting their heads is to have them line up along a cross, such as is found with basketball court lines. Drawing a cross per group in the sand may also be helpful. When done plotting, each student should label their lines with their name.

Questions to think about:

1. Besides hunting, why do some animals need keen binocular vision?
2. Besides watching for predators, why do animals need keen peripheral vision?
3. Why do humans have binocular vision?