Measuring a Clever Octopus: teacher key

Giant Pacific Octopuses, grade 8 edition, written for 8th grade. How do people measure how big and how smart a giant Pacific octopus is? Sources disagree about its record size and its depth, and one octopus named Pandora opened a puzzle jar.

Read the book. Print this page for the key.

Questions and answers

1. How long did Pandora take to open her first puzzle jar?
   • 15 minutes (answer)
   • 2 hours
   • 15 seconds
2. How do wild giant Pacific octopuses find their way back to their dens?
   • By landmarks and the contour of the seafloor (answer)
   • By following the sun
   • By following other octopuses
3. Which sources report a record of more than 600 pounds?
   • Seattle Aquarium
   • National Geographic and National Wildlife magazine (answer)
   • An Alaska species guide
4. What do reference guides disagree about?
   • How many arms it has
   • How deep it lives (answer)
   • What color its blood is
5. Sources give different record sizes. What does that show?
   • Every source measured the same animal
   • The largest recorded size depends on the source (answer)
   • Octopuses do not grow
6. What does invertebrate mean in: the largest of any invertebrate?
   • A fast swimmer
   • An animal without a backbone (answer)
   • A sea plant

Words

• invertebrate: animal without backbone
• neurons: nerve cells
• landmarks: known features
• plankton: drifting life