This page contains content from the Xpeditions website, which is now archived. The National Geographic Education website,, includes some of our most popular archival content in its original format.

Warning Label

Please note: We are no longer updating the content on archived pages. Archived content may contain dated information and broken links.

Grades K-2
This lesson introduces students to the American alligator, the Nile crocodile, and SuperCroc (the prehistoric crocodilian species Sarcosuchus imperator ). Students will learn about each species' geographical range, habitat, diet, and behaviors. They will conclude the lesson by designing zoo habitats for alligators or crocodiles and creating captions providing information about these species' prehistoric relative.
Connections to the Curriculum:
Geography, life sciences
Connections to the National Geography Standards:
Standard 8: "The characteristics and spatial distribution of ecosystems on Earth's surface"
Three to four hours

Materials Required:
  • Computer with Internet access
  • Construction paper
  • Drawing materials
Students will
  • view and answer questions about a map and pictures showing the geographical distribution and characteristics of three crocodilian species;
  • compare SuperCroc's size to the size of modern crocodilians;
  • research and take notes on the American alligator and the Nile crocodile;
  • draw zoo habitats for the American alligator and the Nile crocodile; and
  • write placards to go along with their zoo habitats.
Geographic Skills:
Asking Geographic Questions
Acquiring Geographic Information
Organizing Geographic Information
Answering Geographic Questions
Analyzing Geographic Information

S u g g e s t e d   P r o c e d u r e
Ask students if they have ever seen alligators or crocodiles, either in the wild or at the zoo. How big were the animals they saw? What were their habitats like?

Can students tell the difference between alligators and crocodiles? Explain that one of the most noticeable differences is that alligators have broader snouts than crocodiles. As they go through this lesson, ask them to look carefully at the snouts of the animals pictured to see if they can tell the difference.

Go to the crocodilian distribution map , and link from this map to the Nile crocodile (number 15), the American alligator (number 1), and SuperCroc (the red spot in northern Africa). Have the class look at the pictures of each species.

Tell the class that two of the species pictured are alive today, while one picture is of a species that has been extinct for millions of years. Can they tell which is the extinct species?

Show students the pictures again, this time explaining that SuperCroc is extinct. This species lived approximately 110 million years ago in sub-Saharan Africa. Are they surprised that the extinct SuperCroc looked so similar to today's crocodiles and alligators? What are the similarities and differences?

Have students return to the crocodilian distribution map to see the parts of the world where crocodiles and alligators live and where SuperCroc fossils have been discovered. Discuss these questions: On which continents do crocodiles and alligators live? Can both be found in the United States? Which lives nearer to the students' home region?

Have students link from the map to the Nile crocodile, the American alligator, and SuperCroc. In the lower right of the new window that opens for each species, they will see a comparison of the animal next to a man. Ask them to figure out which is the largest and which is the smallest of these three species (they should notice that SuperCroc was huge!).

Students can see another image of SuperCroc's size related to a man at a distance and close up , and a comparison of SuperCroc's jaw to that of a modern crocodile.

As an option to illustrate SuperCroc's size, have students measure forty feet in the classroom or hallway. This is the length of SuperCroc. How many of them have to stand in line side-by-side to span SuperCroc's long body?

Explain that prehistoric species such as SuperCroc have many things in common with their modern counterparts, such as crocodiles and alligators. Students have probably already noticed this fact by looking at the pictures. What things do they think these species might have in common? What about their diets and habitats? Can students guess anything about these animals' eating habits or habitats by looking at their pictures?

Explain that scientists believe SuperCroc dined on dinosaurs and fish. Its massive jaws enabled it to easily crush its prey. Modern alligators and crocodiles, though much smaller, also have powerful jaws (although they rarely harm people).

Suggested Student Assessment:
Divide the class into small groups or pairs. Have students use Web and print resources to research the Nile crocodile and the American alligator, two of the best known crocodilian species. Ask students to investigate:
  • what they eat;
  • what type of habitat they prefer to live in;
  • where they spend most of their time; and
  • where they lay their eggs.
The following Web sites will be helpful:

Crocodilian Distribution Map Crocodilian Photo Gallery Nile Crocodile Creature Feature

Have groups pretend they have been asked to design a zoo habitat for either an American alligator or a Nile crocodile. The habitats must be comfortable for the animals, with the type of habitat features the animals like and plenty of nutritious food provided by the zoo workers.

Ask students to draw their habitats on construction paper. As an option, they can build model habitats out of Popsicle sticks and other crafts materials.

Have groups conclude by creating placards to be placed in front of the habitats so visitors can learn more about alligators and crocodiles. The placards should describe the animal's natural geographic range, its size, basic behaviors, preferred habitat, and diet. It should conclude with a comparison of this species to SuperCroc, showing the relative sizes of each animal and perhaps a timeline showing when SuperCroc lived.

Extending the Lesson:
Read students the classic story, Lyle, Lyle, Crocodile (Houghton Mifflin Co). This story is fun and obviously unrealistic (Lyle lives in a fancy apartment in New York City). It addresses issues of friendship, being different, and overcoming adversity—outside the scope of this lesson, but important nonetheless.

Ask students to explain how they think a real crocodile would adjust to its new habitat in New York City. Would it be able to live outside during the winter? Where might it look for food in a large city?

Related Links: