Built for the River: teacher key

Nile Crocodiles, grade 9 edition, written for 9th grade. Meet the Nile crocodile, from its river home and its senses to its hunting. Then follow a mother's nest, her eggs and her young, and see how the species is doing.

Read the book. Print this page for the key.

Questions and answers

1. How does a crocodile's heart help it save oxygen under water?
   • It stops beating
   • It grows larger
   • It works like a three-chambered heart (answer)
2. What does the IUCN Red List say about the Nile crocodile, as of November 2026?
   • Least Concern (answer)
   • Almost gone
   • Found in one country
3. What can too much shade over a nest lead to?
   • Mostly male hatchlings
   • No eggs
   • Mostly female hatchlings (answer)
4. Why can a lot of shade over a nest lead to mostly female hatchlings?
   • Shade hides the nest from fish
   • Shade cools the eggs, and nest temperature decides the sex (answer)
   • Shade makes the eggs hatch early
5. When are Nile crocodiles most often active?
   • At night (answer)
   • At noon
   • Only in winter
6. How does a mother carry her newly hatched babies to the water?
   • On her back
   • In her mouth (answer)
   • On her tail

Words

• mangrove: coastal tree swamp
• hatchlings: new babies
• ambush: hidden surprise
• basks: rests in sun