An Old Kind of Animal: teacher key

American Alligators, grade 10 edition, written for 10th grade. Alligators first appeared over 80 million years ago. Read about their hearing, teeth, hunting and the work done to bring them back.

Read the book. Print this page for the key.

Questions and answers

1. About how long ago did the American alligator first appear?
   • About 240 years ago
   • Over 8 thousand years ago
   • Over 80 million years ago (answer)
2. What did a 2011 diet study in Texas find about invertebrates?
   • They made up none of the diet
   • They made up 15.7 to 34.6 percent of alligator diets (answer)
   • They made up all of the diet
3. At what temperature or below do female alligators hatch?
   • 31 degrees Celsius (answer)
   • 13 degrees Celsius
   • 3 degrees Celsius
4. What did the field study find about the tagged alligators' submerged swimming?
   • It averaged 3 meters per second
   • It never happened
   • It averaged 0.31 meters per second (answer)
5. What does invertebrates mean here?
   • Animals with big teeth
   • Animals without backbones (answer)
   • Animals that fly
6. Why can an alligator go through 3,000 teeth in its life?
   • Its teeth are replaced rapidly (answer)
   • It has 3,000 teeth at once
   • It never loses a tooth

Words

• crocodilians: alligators and kin
• hertz: vibrations per second
• invertebrates: animals without backbones
• fractured: cracked or broken
• maturity: full growth