Seasonal changes impel a wide variety of creatures to begin migrations—sometimes on an epic scale—to feeding, mating, and breeding grounds. These journeys sometimes cover thousands of miles and require ingenious methods to accomplish. The following video segments from the Nature film "Earth Navigators" feature different animal species reacting to changes in their environments by migrating from one part of the earth to another.

Clip 1: Planetary Moves—As you watch this video respond to the following questions in your notes. (Video is about 2 minutes long.)

1. What causes the seasons?
2. How does the earth's travel around the sun relate to the movements of animals around the globe?
3. Name the four migrating animals in this clip. Where on the globe does each animal migrate?

Clip 2: Monarch Migration—As you watch this video respond to the following questions using your notes. (Video is about 3 minutes long.)

1. What does the coming of spring trigger for monarch butterflies?
2. Where does the monarch's migration begin? Where are they headed?

Clip 3: Hungry Beasts—As you watch this video respond to the following using your notes. (Video is about 3 minutes long.)

1. Why do wildebeest migrate? Why do locust hoppers migrate? How is the migration of the two animals similar?
2. How many wildebeest might there be in a typical herd? Why do you think the wildebeest travel in such large groups?

Clip 4: Arctic Summer—As you watch this video respond to the following questions using your notes. (Video is about 3 minutes long.)

1. Define the summer solstice. What conditions can you expect above the Arctic circle in summer?
2. Why do so many birds spend the summer in the Arctic?