The
Brown bears like this
one can spend half the
year in a sleep-like state.
Big Sleep
D
ave Garshelis peers
into a hole beneath
a snow-covered
log in Minnesota.
Inside, an American
black bear is taking a long
winter snooze with her cubs.
Even though Garshelis has been
peeking in on sleeping bears for
more than 30 years, he moves
cautiously—sometimes these
230-kilogram (500-pound)
creatures wake up grumpy!
1
Normally, no one should
disturb bears or their cubs.
But Garshelis is a biologist at
the Minnesota Department
of Natural Resources, and his
team is specially trained. “You
have to be careful,” he says.
Garshelis sedates the mother
bear to make sure she stays
asleep. Then his team gets to
work studying the bear and her
cubs. The scientists weigh the
bear and collect blood samples.
They take turns holding the
cubs to keep them warm, like
their mom usually does.
Why is Garshelis poking
around bear dens? He studies
how the bears hibernate in
winter. Hibernating bears can
sleep for seven months straight
without eating, drinking, or
taking a bathroom break.
Most creatures couldn’t
survive like this. Scientists
think that if they can figure
S U P E R S C I E N C E • T O O R D E R , C A L L 1- 8 0 0 - S C H O L A S T I C O r v isit w w w. scholastic . co m / b u y- s u p ersci
Juniors Bildarchiv GmbH/Alamy (hibernating)
Can snoozing
bears help
scientists
cure human
diseases?
watch
a video
subscribers
only
bonus
skills
sheet
See attached.
Ann Arbor Miller/Arbor Photographic (measuring, weighing)
Dave Garshelis
measures a
sedated black
bear. A blindfold
helps the bear
stay calm.
out how bears manage to do
it, they might find new ways to
treat some human diseases.
The Science of Snoozing
Many kinds of bears
hibernate to save energy
during the cold season, when
there isn’t enough food to
eat. While bears hibernate,
their bodies slow down. Their
Scientists hang
a bear cub from
a scale to check
its weight.
temperature drops
by about 6°C (10°F).
Normally, bears
take 15 breaths a
minute and their
hearts beat almost
once a second. But
during hibernation,
they breathe just
twice a minute and their
heartbeats can be more
than 10 seconds apart.
Humans could never
withstand these conditions. “If
your heart stopped for just five
seconds, you’d pass out,” says
Paul Iaizzo, a physiologist from
the University of Minnesota
who works with Garshelis.
To stay alive during their
big sleep, the bears prepare for
months. In the fall, they stuff
themselves with nuts, berries,
and insects. The animals pack
on fat, increasing their body
weight by as much as a third.
In humans, such drastic
weight gain can cause health
problems. About 30 percent
of people who are overweight
develop type 2 diabetes, a
disease that disrupts the body’s
sedate—to give an animal
a drug that makes it relax
or sleep
hibernate—to spend winter in
a sleep-like state with reduced
body functions to save energy
physiologist—a scientist
who studies how living things
function
type 2 diabetes—a disease
that affects the body’s ability to
turn sugar into energy
protein—a microscopic
particle in your body that
performs a particular job
w w w . scholastic . co m / s u p erscie n ce
2
ability to turn the sugar in food
into energy. It can lead to heart
disease and other problems.
Bears pack on the pounds
every year, but unlike
overweight humans, they stay
healthy. How do they do it?
A biologist keeps
a black bear
cub warm while
other scientists
study its mother.
Sleep Study
Kevin Corbit is a scientist
at Amgen, a company in
California that develops new
medicines. Last year, he studied
six captive grizzly bears during
hibernation. He found that the
bears, chubby from eating all
fall, did develop diabetes while
they were hibernating. Their
bodies started processing sugar
How a Bear Hibernates
MUSCLES: A
bear’s muscles
stay strong in
winter, even
though the
animal doesn’t
move for months.
KIDNEYS: These organs normally help remove
waste from the body. But during hibernation,
the bear’s body recycles its waste instead, so
the bear doesn’t have to pee.
HEART: During
hibernation, a
bear’s heart rate
slows down to save
energy. It returns
to its normal rate
in the spring.
BONES: A bear’s bones
weaken when the bear
is inactive. But the
bear’s body produces
a special chemical to
rebuild the lost bone.
3
S U P E R S C I E N C E • T O O R D E R , C A L L 1- 8 0 0 - S C H O L A S T I C O r v isit w w w. scholastic . co m / b u y- s u p ersci
Ann Arbor Miller/Arbor Photographic (biologist); 5W Infographics (bear infographic)
During hibernation, a bear can sleep for up to seven months of the year without eating, drinking,
or going to the bathroom. The animal’s body adjusts to keep it alive in this inactive state.
more slowly so that what they’d
eaten would last all winter.
But in the spring, when the
bears started to eat again, the
diabetes vanished. “They have
natural, reversible diabetes,”
says Corbit. “It’s very cool.”
Corbit discovered that bears
have a special protein in their
bodies that makes this possible.
It works like a dimmer switch,
he says. Depending on how
much the bears are eating, it
adjusts up or down to control
how their bodies process sugar.
Corbit hopes to develop a
drug for people that mimics
this protein. It could switch off
diabetes in humans just like
it does in bears each spring.
Aimee Herring (Hands On)
Helping Humans
Diabetes isn’t the only illness
scientists studying bears hope
to treat. Iaizzo, the physiologist
in Minnesota, focuses on bears’
hearts. He’s found that when
a bear’s heart slows down, its
body releases chemicals that
protect its other organs from
damage. He hopes a medicine
made from these chemicals
could help people with heart
problems stay healthy.
Scientists need to do a lot
more research to develop these
drugs. But they’re hopeful that
the clues from bears will help.
“Bears are out in nature,
perfectly healthy, doing all
these things that make humans
sick,” says Corbit. Maybe
their slumber holds the key to
keeping humans healthy too.
­— Stephanie Warren Drimmer
Keeping Warm
Which material holds in more heat?
Observe: In the fall, bears pack
on fat. This helps keep them
warm while they hibernate.
Ask a Research Question:
How well does fat keep an
animal warm compared with
cotton clothes?
Form a Hypothesis Based on
This Question: Which material
will keep a hand warmer in icy
water: fat or cotton?
covered in fat.
Your partner can help
by squishing the bag from
the outside. Have your partner
place a rubber band around
your wrist to secure the bag.
5. Put the sock over your
right hand. Put this hand into
another plastic bag and have
your partner secure it.
6. Dip both hands in the ice
Materials: smocks or aprons
• newspaper • large bowl or
bucket • measuring cups • cold
water • 2 cups of ice cubes •
solid vegetable shortening (like
Crisco) • quart-size zip-top
bags • spoon • rubber bands •
cotton sock • stopwatch
water for 30 seconds. (Be
careful not to let water into
the bags.) While your partner
keeps time, pay attention to
how each hand feels.
1. Work with a partner. Put on
Procedure:
your hands. Switch roles with
your partner and repeat steps 3
through 7.
2. Fill the bowl with 8 cups of
Results: Which of your hands
got cold faster?
3. Have your partner scoop 3/4
1. Which bag kept your hand
smocks and spread newspaper
on the table. This gets messy!
cold water. Add the ice cubes.
7. Remove your hands from the
water. How do they feel now?
8. Take off the bags and wash
Conclusions:
cup of shortening into a zip-top
bag. Shortening is a type of fat.
Use the spoon to scrape it all in.
warmer? Did your partner get
the same results?
4. Place your left hand in the
bag. Wiggle it around until it’s
would fat or cotton better
protect an animal in the cold?
2. Based on your observations,
Step 4
View
a slide
show
subscribers
only
PAGE 1
life science
The Big Sleep
Lexile Level 930; Guided Reading Level V
OBJECTIVE
Learn why and how bears hibernate and why
scientists are studying hibernation to help
treat human diseases.
SET UP
1. D
raw three columns on the board.
Label them “Adaptation,” “Example,”
and “Physical or Behavioral?” In the
Adaptation column, write: thorns,
hibernation, camouflage, and
playing dead.
2. Print photos of a black bear, a
chameleon, an opossum, and a rose
bush. Tape them to the board.
BEFORE READING
1. E
xplain that living things have physical
and behavioral adaptations. A behavioral
adaptation is when an organism acts a
certain way. A physical adaptation is a
body part that functions a certain way.
2. R
ead each adaptation from the list
and ask:
•Which of the organisms pictured uses this
adaptation? (thorns = rose; hibernation
= bear; camouflage = chameleon; playing
dead = opossum)
•Is the adaptation physical, behavioral, or
both? (behavioral: playing dead; physical:
thorns, camouflage; both: hibernation)
3. Place each photo next to its adaptation,
and write P, B, or both in the third column.
AFTER READING
•Why do bears hibernate? (to conserve
energy during cold months, when there’s
less food)
•What are some diseases scientists
studying hibernation hope to treat?
(diabetes, heart disease)
RESOURCE
visit the following website for more
hibernation lessons from Scholastic
Instructor:
www.scholastic.com/teachers/lesson-plan/time-sleep
Reading and literacy connection
Offer students the 10-question, multiple-choice “No-Sweat Bubble Test”
skills sheet below. (The activity is also available to subscribers in our
Teacher’s Guide and at our website.) Students answer a variety of reading
comprehension questions about the article.
Common Core State Standard
Reading Informational Text: 1
To order SuperScience, call 1-800-SCHOLASTIC or click here.
READING COMPREHENSION
Name: ______________________________________
Date: _________________
No-Sweat Bubble Test
Directions: Read each question below, then use the article “The Big Sleep” to determine the best answer.
Completely fill in the bubble next to the best answer.
1. Bears can hibernate for up to ___ of the year.
A
B
C
D
30 days
3 months
7 months
9 months
6. Which part of a bear’s body processes waste?
A heart
B pancreas Cbone
D kidney
7. Which word is a synonym for slumber?
A to hide from predators
B to save energy during cold months when
there’s less food
C to give birth to their cubs
D to keep their bodies warmer during
cold months
3. What does a bear do to prepare for hibernation?
A eat extra food
B dig a deep hole
C take a lot of naps
D all of the above
4. What happens to a bear when it hibernates?
A
B
C
D
Its body temperature decreases.
Its heart rate decreases.
Its breathing rate slows down.
all of the above
turn ___ from food into ___.
A fat; energy
B sugar; energy
C energy; fat
D energy; sugar
9. Which of the following statements is TRUE?
A M
other bears keep their cubs warm during
hibernation.
B Bears take breaks from hibernating to go to
the bathroom.
C All types of bears hibernate.
D During hibernation, a bear’s heart rate
increases.
10. Which sentence BEST represents the main
idea of the article?
5. Which disease did scientists discover is
Visit www.scholastic.com/superscience
Cspeedy
Dsick
8. Diabetes interferes with the body’s ability to
reversible in bears?
A rabies
B diabetes
C asthma
D ringworm
A sleep
B wobble
A B
ears have serious health problems from
being overweight.
B A bear’s heart rate drops during
hibernation.
C Scientists can learn about some human
diseases by studying how bears hibernate.
D Scientists who study hibernation have
dangerous jobs.
To order, call 1-800-SCHOLASTIC or visit www.scholastic.com/buy-supersci
PERMISSION GRANTED TO REPRODUCE FOR CLASSROOM USE ONLY. ©2015 BY SCHOLASTIC INC.
2. What is the main reason bears hibernate?