Open Questions About Grizzlies: teacher key

Grizzly Bears, grade 12 edition, written for 12th grade and up. What triggers a bear's winter sleep? How many kinds of grizzly are there? See what scientists know and what they are still working out.

Read the book. Print this page for the key.

Questions and answers

1. Why did researchers study free-ranging brown bears?
   • Little is known about what triggers or ends hibernation in the wild (answer)
   • Bears cannot be studied in labs
   • Bears hibernate only in summer
2. What do researchers think likely triggers hibernation?
   • Snow in spring
   • Food in autumn (answer)
   • Salmon in summer
3. What word does a U.S. Department of the Interior page use for the winter sleep?
   • Migration
   • Spawning
   • Torpor (answer)
4. One source says torpor and researchers say shallow hibernators. What does this show?
   • Sources use different words for the winter sleep (answer)
   • Bears do not sleep in winter
   • Bears sleep in summer
5. What have Wyoming, Montana and Idaho asked the U.S. Fish and Wildlife Service to consider?
   • Adding more grizzlies to the list
   • Removing Greater Yellowstone grizzlies from Threatened Species status (answer)
   • Moving bears to Canada
6. How do scientists judge whether the Greater Yellowstone population has recovered?
   • By counting trout
   • By measuring snow
   • By population size, where females with cubs live, and how many bears die each year (answer)

Words

• torpor: deep rest
• subspecies: kind within species
• hibernation: deep winter sleep