Sensing the Water: teacher key

American Alligators, grade 9 edition, written for 9th grade. Read about how alligators dive, sense tiny ripples, hunt and grow, and how scientists have followed them.

Read the book. Print this page for the key.

Questions and answers

1. In 2002, what did alligators in a dark aquarium turn to face?
   • A bright lamp
   • Single drops of water (answer)
   • A school of fish
2. What did a field study of tagged alligators in the Banana River Lagoon find about their dives?
   • They lasted about 310 seconds (answer)
   • They lasted a full day
   • They went 30 meters deep
3. How slow can an alligator hiding under water make its heart beat?
   • 200 beats per minute
   • 20 beats per day
   • 2 or 3 beats per minute (answer)
4. Alligators are more closely related to which group?
   • Lizards
   • Birds and dinosaurs (answer)
   • Snakes
5. What does clutch mean here?
   • A group of eggs (answer)
   • A kind of dive
   • A tiny ripple
6. Some touch sensors in alligator skin are tuned to 20 to 35 hertz. What does that suit?
   • Loud thunder
   • Bright sunlight
   • Tiny water ripples (answer)

Words

• crocodilians: alligators and kin
• nostrils: nose openings
• hertz: vibrations per second
• clutch: group of eggs
• captive: kept in care