Slow Motion Strike: teacher key

Barracudas, grade 9 edition, written for 9th grade. High-speed cameras and jaw models show how a great barracuda hunts. Read what scientists measured, and one thing they still cannot say.

Read the book. Print this page for the key.

Questions and answers

1. What was the average strike velocity measured for the great barracuda?
   • 64 cm/s
   • 144 cm/s (answer)
   • 7000 cm/s
2. When does a great barracuda close its jaws?
   • Before the prey is inside its mouth
   • Only after the prey is already inside its mouth (answer)
   • It never closes them
3. What is true of the 9 newton bite force?
   • It is a prediction from jaw anatomy (answer)
   • It was measured on a living fish
   • It is the speed of the lunge
4. Why do scientists say the spawning of great barracudas is a mystery?
   • Sources give different answers about when and where (answer)
   • Barracudas have no eggs
   • Everyone agrees it is in spring
5. What does spawn mean in: when and where great barracudas spawn?
   • Swim fast
   • Lay eggs (answer)
   • Change color

Words

• ambush: wait and surprise
• velocity: speed and direction
• newtons: units of force
• spawn: lay eggs
• specimens: collected animals