One Eye Open: teacher key

How Animals Sleep, grade 9 edition, written for 9th grade. A dolphin rests half its brain, a fur seal can open one eye while half its brain sleeps, and a bird may sleep in flight. Learn how animals sleep and stay alert at once.

Read the book. Print this page for the key.

Questions and answers

1. What do birds that sleep with half a brain do with their eyes?
   • Close only one eye (answer)
   • Close both eyes
   • Keep both eyes shut tight
2. How were the sperm whales called asleep?
   • By brain waves
   • By reduced responsiveness that reverses with enough stimulation (answer)
   • By their snoring
3. How long did frigatebirds sleep each day in flight?
   • About 0.69 hours (answer)
   • About 10 hours
   • None
4. What does the fur seal's open eye show?
   • One half of its brain can be asleep while the other half stays awake (answer)
   • It is blind
   • It never sleeps
5. What do sleep, torpor and hibernation have in common?
   • Slowed heart rate and lower body temperature (answer)
   • They happen only in summer
   • They are the same thing
6. What does acetylcholine mean here?
   • A brain chemical (answer)
   • A kind of eye
   • A deep dive

Words

• acetylcholine: a brain chemical
• unihemispheric: one half-brain
• paralysis: unable to move
• torpor: deep rest
• matriarchs: lead females