Secrets of the Crocodile Caves

Student Handout

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Madagascar is home to a wide variety of organisms that occupy specific niches. Each species is connected to other species through a food web and depends on other species for survival. Learn about just some of those relationships in this activity.

Procedure

1. Take careful notes of all the animals as you watch NOVA's "Secrets of the Crocodile Caves." Then label all the plants and animals in this illustration. Draw arrows from each plant or animal to the animal that eats it.

2. On a separate sheet of paper, draw a food web of all the plants and animals. Write the names of all the plants and animals and draw arrows from each plant or animal to the animal that eats it.

3. Choose a food chain from within your food web and draw an energy pyramid with the parts of that food chain. To create your energy pyramid, draw a triangle and divide it into a top, middle, and bottom. Show how energy flows through the food chain by writing the plant in the bottom segment, animal that eat the plants in the middle, and animal that eat that animal at the top.

Questions
Write your answers on a separate sheet of paper.

1. Circle the crowned lemur on your food web. Identify what the crowned lemur eats in the rainy and dry seasons. List the crowned lemur's predators and competitors.

2. If the fig trees were struck by disease, how would the population of crowned lemurs be affected? How would the crowned lemurs' predators be affected? How would this affect the entire food web?

3. Circle the crocodile. What does the crocodile eat? The adult crocodile in the Ankarana region of Madagascar is free from predators because the Ankarana tribe holds the crocodile sacred. What other factors affect the population of crocodiles? What dangers threaten the eggs and the young crocodiles?