Black bears hibernate to get through winter. TUCHONG
With low temperatures and a lack of food, winter is a harsh season for animals. Many animals enter hibernation to get through it.
Hibernation is when an animal goes into a state of extended inactivity. Animals hide away from predators. Their metabolism will slow to less than a quarter of its normal rate. This cools the creature’s body and slows its heartbeat to just a few times per minute, for up to months at a time.
But why don’t humans hibernate? Human hibernation doesn’t exist for many reasons. Our body is not designed for hibernation. Our evolutionary ancestors were tropical animals with no history of hibernating: Humans have only migrated into temperate and subarctic latitudes in the last hundred thousand years or so. That’s not quite long enough to evolve all the metabolic adaptations we would need to be able to hibernate, according to the BBC Science Focus Magazine.
For example, waste management is a huge challenge for human hibernation. Animals that hibernate are able to essentially stop their urination and defecation during hibernation, sometimes through a process of reabsorption to preserve nutrients. Unfortunately, humans can’t do this.
There are other challenges. Body temperatures below 2.8 C tend to disrupt the human digestive tract and may cause pain. Cold temperatures can also suppress the immune system, making people more vulnerable to infections, according to Smithsonian Magazine.
In fact, humans don’t need to sleep through winter. We have discovered fire, clothes, shelter, hunting and agriculture, all of which are much more effective ways of surviving the cold.
Could humans hibernate in the future? For long-distance space travel, it’s likely. A journey to Mars would take around months using current technology. If we hope to visit another star system, even if we could travel at the speed of light, the journey would take years. Being able to hibernate would make such distances considerably less boring for the astronauts and conserve vital resources, according to University of Oxford in the UK.
NASA is treating this question seriously. Beginning in 2014, the agency funded research on long-term hibernation as a way to facilitate long-term space travel, according to The Atlantic magazine.