Animals over Winter
How do habitats change?
• Temperature decreases
– As low as −50°C in the
Arctic! Sometimes even
colder!
• Hours of daylight decrease
– In some places it is dark for
over four months!
• Increased rain and snowfall
– (especially in the northern
hemisphere)
• Food supplies may be harder to find
American bison in summer habitat
http://www.arkive.org/american-bison/bison-bison/video-bi02.html
American bison in winter
Brrr – it’s cold!
What do animals do in winter?
Animals
can…
• Migrate
• Hibernate
• Stay in the area and:
- Store food
- Change their appearance
- Change their behaviour
Polar bear sleeping in the snow
Complete the worksheet
Answers!
Migration
• This means: to move from one region, country or
climate to another
• In winter, migrating animals normally move from a
colder climate to a warmer one
Snow geese migrating: flying in a ‘V’ formation
Snow geese being taught to migrate by following
a microlight aircraft
Snow goose: Migration case
study
• Migrate to a warmer
climate in winter
• Spend spring and
summer in the Arctic
(Alaska, Greenland, Canada)
• Fly south to a warmer
climate in autumn
Snow geese migrating
• Overwinter in Mexico and the Gulf Coast
• Some birds fly all the way in one flight!
- 1,700 miles in 70 hours
Monarch butterfly: Migration
case study
• Longest known insect
migration
• North American and Canada
populations migrate southward
to overwinter
- Up to 3000 miles!
- Cover 80 miles per day!
• Millions of individuals roost
throughout winter in a state of
relative inactivity
Hibernation
• This means to go into a
dormant (torpid) state
over winter
• Sliding scale of hibernation:
- Some animals hibernate
throughout winter
- Some animals wake up to
feed
Brown long-eared bat hibernating
True hibernation
• Body temperature drops
• Metabolic rate slows
• Breathing and heart rate
decreases
• Live off stored fat reserves
• Can lose up to 40% of
body weight
Common dormouse hibernating
True hibernator: Arctic
ground squirrel
• Unique amongst mammal
hibernators as their body
temperature drops to -3ºC!
• Every few weeks they warm up
slightly by shivering
- Possibly to prevent brain
damage
• Risky strategy:
- Some Arctic ground squirrels
never wake up
Arctic ground squirrel
True hibernator: painted turtle
• Spend winter
hibernating at the
bottom of a river bed
• Can hibernate for
up to six months
• Use a ‘natural
antifreeze’ to prevent their blood from
freezing
Painted turtle
Partial hibernation
• Body temperature
drops (but often not as
low as true hibernators)
• Breathing and heart
rate slow (but often not
as slow as true
hibernators)
Brown bear: a full and partial hibernator
• Can be more easily woken than true hibernators
(can wake up in case of danger)
• Awake to feed, drink and even walk around
Resident animals
Animals which stay in the same area and
change their behaviour or appearance rather
than hibernating or migrating.
Reindeer in winter coat
What can resident animals do?
• Store food
• Change their diet
• Change their coat
colour
• Grow a thicker coat
Skunks change their diet in winter
• Lay down a thick layer of fat
• Decrease their metabolic rate
Arctic fox: Adaptations to
the survive the winter
Arctic fox in winter coat
Arctic fox in summer coat
What about species that live in even
colder places?
Thick layer of fat
(blubber) under the
skin for insulation
Thick skin
Cold feet!
Huddle
together for
warmth
Large body
size (loses
less heat)
Tightly overlapping
feathers for waterproofing
and warmth
Light-coloured
fur
Hollow fur
to trap air
for
insulation
Thick layer
of fat
under the
skin
Black skin
(retains heat)
Large body size to
minimise heat
loss
Large feet
to spread
weight on
ice/snow
Small ears
and tail to
reduce
heat loss
Stiff hairs on feet to
protect from the cold
and provide grip
‘Waking
hibernation’
Any Questions?
Let’s move on to the activity…
Activity
• Choose one of the species from the list.
• Make a poster about your species. What is it
called? Where does it live?
• Using the ARKive website and other websites,
find out about the different adaptations your
species has to survive winter.
• Draw a picture and explain the different
adaptations your species has to survive…
–
–
–
–
Does it migrate?
Does it hibernate?
Does it grow a thick coat?
Does it store food?
Species to choose from
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•
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Bar-headed goose
Grey squirrel
American bison
Stoat
Arctic tern
Dormouse
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Garter snake
Blue whale
Arctic fox
Skunk
Brown bear
Swallow