By Amruth Chinnappa
The cold days of winter herald a period of inactivity in animals, characterized by reduced metabolism when actions such as eating, drinking and excretion are put on hold. This decrease in function is seen in a variety of creatures and enables them to live through periods of scarcity of food. The body experiences a reduction in temperature, slower breathing and a lower blood flow, relying on fat deposits in the body to eke out the bare minimum of energy necessary for survival.
Mission survival: Hibernate
Hibernating creatures are safe from the dangers of the wild and are found to have a nearly 100% rate of survival. The hibernation period increases for smaller creatures as they have a lesser capacity to store food and need more energy to survive. Another reason for the long stasis period has been attributed to safety as well. The longest observed period of hibernation was of a pygmy possum which lay in dormancy for a whopping 367 days!
This does not mean that they spend the whole duration asleep. Hibernation has also been observed in mammals, fishes and reptiles with varied levels of inactivity, where some species rely on a near-sleep state called torpor to get through the day. These creatures exhibit brief periods of activity amid their state of rest. Generally, reptiles show a higher degree of awareness during hibernation than mammals and respond to external stimuli.
Evolution and hibernation
At minus 3 degrees centigrade, Arctic ground squirrels have one of the lowest recorded body temperatures during hibernation. Although these extreme reactions are a product of external stimuli and are necessary for survival, the same behaviour is found to exist in domesticated creatures as well. A cosy bed and timely food do not seem to affect hibernation except for a slightly higher rate of activity.
Evolution has ingrained in animals, a circadian clock which directs their behaviour and activity over long periods of time. It plays a major part in the working of a body, with every cell having a certain set of repeated activities assigned to it.
Can the human body have similar effects?
The Nobel Prize in medicine, 2017 was awarded to 3 researchers on their discovery of PER and TIM proteins which help in creating the Circadian rhythm of the cells in a fruit fly. Similarly, a molecule called Adenosine has been found to affect the hibernation pattern of animals and research on arctic ground squirrels has provided conclusive evidence in this regard.
A state of torpor was induced in the squirrels when the neurons attached to adenosine were excited implying that similar effects might be seen in a human body as well.
Animals vs humans
During hibernation, brown fat provides the energy needed for the functioning of the body. This is different from white fat cells resulting from McDonald’s and late night food binges, which only serve to store calories. Brown fat cells are instrumental in acting as a warm jacket, helping you keep warm. It is found in every human to a small degree but more so in babies who do not have the ability to shiver on feeling cold. In animals, these fat cells act as reserves during hibernation and keep them warm.
Humans have evolved a higher mental faculty and do not need to hibernate to survive the winter. There hasnt existed an evolutionary need for it but there is no doubt that some of our earliest ancestors must have practised it in one form or the other. Genetic memories ingrained in our cells serve as a reminder of our past. There are multiple instances of human bodies acting well outside the norm in cases of extreme stress. Rescued hikers survive under several feet of snow because their metabolism slows down to suit the environment.
Death: Just a long nap?
Mankind has always viewed the shackles of time as a bother and seeks to move past it. There are a number of movies where the character enters an artificially induced hibernation and wakes up in a vastly futuristic timeline. Although such a technology is currently steeped in fiction, cryogenics is a developing field with investors donating millions of dollars toward its research.
The idea of this procedure acts as a source of comfort to the elderly and ailing who get frozen in the hope of waking up to an advanced future. A British schoolgirl who elected to undergo this method wrote, …I want to live and live longer and I think that in the future they might find a cure for my cancer and wake me up.
If perfected, cryogenics would have huge repercussions in society. It would definitely change the way we look at death, as being a particularly long nap.
Featured Image Source: Rodrigo Soldon 2 via Visual hunt / CC BY-ND