Hibernation, estivation, and torpor are strategies that allow animals to conserve energy and survive periods of cold, heat, or low food availability. Hibernation involves going into a deep sleep-like state during winter where body processes slow down significantly. Estivation occurs during hot weather and involves similar slowing of bodily functions. Torpor is a short-term state of inactivity used to save energy during times of food scarcity. Examples of animals that use these strategies include bats, hedgehogs, ground squirrels, snails, and bears.

1. What is Hibernation?
Hibernation is the way that some animals adopt
to the climate and land around them during
winter.
A hibernating animal will enter into a very ‘deep
sleep’.
While in a state of true hibernation, the animal
will appear to be dead.
There is no movement and it takes a long time for
the animal to wake up.

2. When an animal hibernate its:
breathing and heart rate slow down .
and its body temperature goes down for a
relatively long period. Because it is a “deep
sleep,”.
 Returning from hibernation may take a few
hours.

3. Preparation for the hibernation:
As preparation for the hibernation stage:
 animals accumulate fat in autumn. The
stored fat will be used when the temperature
gets colder in the winter.
 Hibernation is not a continuous process.
Some animals may wake up from hibernation
to eat, drink.

4. Animal also wake up clean themselves, and then
go back to inactivity. Some animals may
hibernate anywhere from a few days to several
months.
Common animals that hibernate are bears, mouse
lemurs, and ground squirrels.
Why Do Animals Hibernate?
It’s COLD.
Hibernation allows the animal to sleep through
the intense cold of winter.
 Scarcity of food and resources.

5. How Do They Survive?
All Animals require energy to do things
such as walk, run, and hunt for food.
Animals also need energy to run the
basic functions of the body, such as
respiration, metabolism, etc.
It is how an animal is able to store and
utilize this energy .

6. Can All Animals Hibernate?
Most animals are not capable of hibernating
because they lack the amount of fat.
Animals that hibernate also put on another
type of fat called “brown fat”.

7. What is “Brown Fat”?
Brown fat, also known as “brown adipose
tissue”, is a special type of fat that is found
across the back and shoulders of hibernating
animals, close to the animal's organs, such
as the brain or liver.
When an animal wakes from its slumber,
brown fat helps to deliver fast energy and
heat to the waking animal.

10. Examples:
1.Bats
Bats are interesting for so many reasons:
They're the only true flying mammals,
they navigate using echolocation.
They have been around since the dinosaur
days and they hibernate.
Bats go into a true hibernation, meaning
they are in such a deep sleep that they may
appear to be dead.

11. . During hibernation, a bat's heart rate drops from
400 to 25 beats per minute, and its breathing
slows so much that it might not take a breath for
up to an hour.
Bats hibernate in the :
 cavities of large trees.
 caves.
 old mine shafts.
 old wells.
 Depending on the species of bat, it either
hibernates alone or in a group.

12. 2. Hedgehogs
Hedgehogs hibernate anywhere from a few
weeks to six months, depending on the
weather.
 During hibernation, their heart rate drops
almost 90 percent. They wake briefly if their
body temperatures drop too low and let their
waking heart rate warm their bodies up
before going back into hibernation.

13. 3. Ground Squirrels
Most types of ground squirrels hibernate and
some do so for nine months a year.
 They also torpor (light hibernation) during other
times of the year for a few days at a time.
Ground squirrels have great hibernation spaces.
They dig elaborate underground tunnels with
different rooms for food storage, sleep and
elimination (yes, they have bathrooms).

14. Estivation
also called “aestivation,”.
Estivation is a strategy used mainly by desert and
tropical animals to get through an extremely hot and
dry weather.
To survive, animals dig into the ground where they
remain idle and cool.
In doing so:
they decrease their metabolic activity.
save energy.
conserve water in their bodies.
And protect themselves from dying due to intense
heat and dryness.

15. Examples:
1. snail
Some creatures that estivate can rapidly return to their
normal condition when there is a need to. Certain snail
species can go back to their original state after only ten
minutes of estivation. However, some animals are capable
of estivation for long periods of time.
2.Lungfish
Lungfish can estivate for as long as three years by coating
itself with mucus that preserves the moisture inside its
cocoon when it is dormant. Lungfish is also a primitive
fish that still has lungs so it can breathe without water.

16. 3.When do dolphins estivate?
Dolphins estivate, or sleep, in the summer. They
can sleep standing up or bedded down on the
ground. Bottle-nosed dolphins sleep during the
night, floating about a foot under the water.

17. 4.Hedgehogs
Hedgehogs also go into estivation when the
weather is really hot. Estivation is like
hibernation, except for it takes place during
hot weather, instead of cold weather.
 Other animals that use this technique include
crabs, lemurs, crocodiles, and desert
hedgehogs.

19. Torpor
, Also called “daily torpor,” is a state of short-
term and involuntary inactivity an animal goes
through to survive and save energy when there
is a decreased food supply.
It is characterized by:
 decreased body temperature
and slower breathing,
heart rate,
 and metabolic rates.

20.  Daily torpor usually lasts less than 24 hours,
which is why some people say it is “light
hibernation.”
“Daily torpor” may happen any time of the year
and does not necessarily occur during the winter
or summer.
 When the animal is not torpid, its body
temperature and metabolic levels are normal.
Animals that go on daily torpor are dormice,
birds, marsupials, and bats.

21. Example :
1. Bears
 Bears aren’t true hibernators. They are more like
light hibernators. Instead of hibernating, bears go
into what is called a torpor.
 The main difference between a torpor and a
hibernation is that during a torpor the animal is
easily awoken.
Bears go into a torpor during the winter months
only if they live in cold areas. During their torpor,
they don’t eat or drink for about 6 months on
average .