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Hibernation – is it a type of sleep?

May 10, 2022

Hibernation – is it a type of sleep?

Nature is just perfect. Nothing happens for no reason and even the most basic biological processes within animals and human beings have an incredible level of complexity. Sleep is most likely to win the prize in this matter. There are many types of sleep and, in addition to sleep types, there are complex sleep mechanisms. Hibernation is on the podium as one of the most amazing sleep mechanisms to study and we are dissecting it in this article. Continue reading to know more about this matter and understand why bears’ hibernation is one of the greatest myths of all time.

Sleep types

When it comes to humans, we can immediately think about deep sleep, light sleep, or even nap. However, scientifically, there are two basic types of sleep:  rapid eye movement (REM) sleep and non-REM sleep. The latter includes the 3 stages that came to our mind – relatively light sleep, light sleep, and deep sleep. The REM type is approximately the first 90 minutes after falling asleep, and where most dreams take place.

In addition to sleep types, there are sleep mechanisms such as circadian rhythms (we already wrote about this here) and sleep-wake homeostasis (which is our inner alarm clock that reminds the body that it’s time to sleep). This is the human sleep process as summarized as possible. Sounds complex? It’s nothing compared to animals.

Hibernation vs Sleep

Have you ever wished to be a bear and be capable to sleep through the whole winter? Well, as appealing as it seems to be, it’s one of nature’s greatest myths. Not even bears do that. Hibernation is indeed an animal’s mechanism like sleep, but bears do not hibernate (no need to tell the truth to your kids though). They do something similar called torpor which is more like taking long naps.

What do these types have in common? They’re both survival tactics and different from sleep. Difference is:

  • Brain activity – it slows down a bit but continues to appear normal to the animal.
  • Waking up time – it’s not easy to wake up from hibernation and animals do need deep sleep afterward to recover.
  • Length – hibernation can take days, weeks, or even months while sleeping is something most animals and all humans do on a regular daily basis.

Only small-sized animals can hibernate and many do, including mammals, birds, and even fish. True hibernators are deer mice, ground squirrels, snakes, bees, woodchucks, and some bats.

It’s a clever survival tactic to adapt to the environment when the weather is severe, the food is scarce, or even when there is the need to face catastrophic events such as forest fires.

During hibernation, an animal’s metabolism, heart rate, and breathing all slow down, while their body temperature drops abruptly, sometimes to freezing temperatures. Animals enter hibernation to conserve their energy. Some may wake up for short periods to eat, drink, defecate or even give birth but many just stay still for months. The act of waking up itself accounts for a large amount of energy and it’s not recommended for true hibernators. Climate change is seriously affecting hibernation natural periods, causing the death of many who wake up before time and struggle with the lack of resources available.

Why do some animals hibernate and others torpor?

The main difference is that hibernation is voluntary.  The animal plans and does so to face the previously stated challenges. It can be considered a deep sleep while torpor is a light sleep and it’s involuntary.

As mentioned in an article that explains the difference between hibernation and torpor – “(…) torpor appears to be a state that an animal enters as the conditions dictate.” Torpor lasts for short periods of time – sometimes just through the night or day depending upon the feeding pattern of the animal. This state is triggered by ambient temperature and the availability of food. Bears, raccoons, and skunks are all “light hibernators” that use torpor to survive the winter.

3 Curiosities on Hibernation

  1. Hibernation or torpor are survival tactics for mammals, as Brumation is for cold-blooded such as snakes and turtles, and diapause is for insects. The only birds in the world that can truly hibernate, or torpor are the Poorwills. Also, the only fish that adopts a winter survival strategy similar to hibernation is the Antarctic cod.
  2. Small-sized animals who hibernate have a 15% higher survival rate and 50% longer lifespan than similarly sized animals who don’t hibernate.
  3. Animals can also hibernate in Summer to protect themselves from high temperatures. The tactic is named estivation and it’s used by animals such as mollusks, crabs, or some hedgehogs.

Finally, can humans hibernate or torpor? Well, it depends. Have you tried sleeping on an Ergomotion® bed? Many already reported a similar effect to torpor.

Sources & Statements:

Small-sized animals who hibernate have a 15% higher survival rate (23) and 50% longer lifespan than similarly sized animals who don’t hibernate.

As a cold-blooded species, reptiles can’t regulate their body temperature in the same way mammals can. Instead of hibernating, they brumate. During brumation, turtles, snakes, and frogs burrow underground or underwater to stay warm.

Hibernation is an extended form of torpor, not sleep. A state where metabolism is depressed to less than five percent of normal.

Animals can quite literally shut themselves off for weeks at a time. Bears can sleep more than 100 days without eating, drinking, or passing waste! Instead, bears can literally turn their pee into protein through a urea recycling process. Why do some animals hibernate and others torpor? The difference is accounted for by the size of the animal. The body of a bear, for instance, is too big to lose all the body temperature necessary to hibernate. The bear’s body never gets too cold (sub-zero temperatures) as the body of a smaller animal does.

When a period of torpor lasts longer than 24 hours, it is hibernation. When animals are in torpor for less than 24 hours, it is considered daily torpor.

“Not that many animals truly hibernate. Many enter a lighter state of sleep called torpor.” / Numbness