Animals over Winter

• 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)

How do habitats change?

• 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?

• Migrate

• Hibernate

• Stay in the area and:

- Store food

- Change their appearance

- Change their behaviour

Polar bear sleeping in the snow

Animals

can…

Complete the worksheet

Answers!

• 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

Migration

Snow geese being taught to migrate by following

a microlight aircraft Snow geese migrating: flying in a ‘V’ formation

• 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

• Overwinter in Mexico and the Gulf Coast

• Some birds fly all the way in one flight!

- 1,700 miles in 70 hours

Snow goose: Migration case

study

Snow geese migrating

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

• 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

Hibernation

Brown long-eared bat hibernating

• Body temperature drops

• Metabolic rate slows

• Breathing and heart rate

decreases

• Live off stored fat reserves

• Can lose up to 40% of

body weight

True hibernation

Common dormouse hibernating

• 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

True hibernator: Arctic

ground squirrel

Arctic ground squirrel

True hibernator: painted turtle

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

• Body temperature drops

(but often not as low as true

hibernators)

• Breathing and heart rate

slow (but often not as slow

as true hibernators)

Partial hibernation

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

Animals which stay in the same area and change their

behaviour or appearance rather than hibernating or

migrating.

Reindeer in winter coat

Resident animals

• Store food

• Change their diet

• Change their coat

colour

• Grow a thicker coat

• Lay down a thick layer of fat

• Decrease their metabolic rate

What can resident animals do?

Skunks change their diet in winter

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

Huddle

together for

warmth

Tightly overlapping

feathers for waterproofing

and warmth

Large body

size (loses

less heat) Cold feet!

Light-coloured

fur

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

Stiff hairs on feet to

protect from the cold

and provide grip

Small ears

and tail to

reduce

heat loss

Hollow fur

to trap air

for

insulation

‘Waking

hibernation’

• Bar-headed goose

• Grey squirrel

• American bison

• Stoat

• Arctic tern

• Dormouse

• Garter snake

• Blue whale

• Arctic fox

• Skunk

• Brown bear

• Swallow

EXTENSION: Design a poster about one

of these animals