Facts About Hibernation and Supecooling

Decoding how some creatures put their lives on hold may bring about therapies for an assortment of human diseases. Human hibernation is indeed a hot topic in the Journal of British Interplanetary Science. Space agencies are concerned since the power to hibernate on demand would come in handy on long run space travel. The immortality bunch is interested as well. If you have an incurable disease or just won't settle for an 80-year-life span, it should be great if you can put your head down, grab forty million winks, and awake when medical science has caught up. Some of the applications aren't all so futuristic; they are practically closer to home. For example, findings from hibernation biology would be valuable in treating everything from hypothermia, heart conditions and obesity.

It is argued that there is enormous potential for applying hibernation schemes to enhance the human condition. Investigating further would lead you to discover that hibernation takes different types in different creatures. A black bear, for instance, lowers its body temperature just by a couple of degrees, and passes the winter in a sort of deep and uninterrupted sleep. Throughout that period, it does not urinate or defecate. For little mammals like ground squirrels and bats, in counterpoint, hibernation generally boasts heavy cut down in body temperature, wherein the animal is inactive, emphasized by steady bouts of thawing up to normal temperature and awakening into activity for a few hours. Particularly, the Arctic ground squirrel might be the most extreme example. Throughout regular life, its center body temperature, similar as ours, is around 98.6 degrees Fahrenheit. But in hibernation, its core body temperature can just come down below freezing, to as little as 26.8 degrees, for many days at a time.

How can Arctic ground squirrels handle hibernation? They supercool. Supercooling is what passes if the temperature of a fluid goes under its freezing point yet does not freeze. That can occur if a liquid bears no nucleating agents—no particles wherein crystals can form. But if you add a particle, like a piece of ice to a cupful of supercooled water, instantly the entire cup of water will freeze! The ability to supercool is uncommon among mammals—but not rare in insects. Like in Alaska, yellow-jacket queens of the species Vespula vulgaris endure the cold, suspended by their mandibles for 9 months in a dry, snow-free cavity, by letting the fluids inside their bodies to supercool. A supercooled yellow-jacket may drop her temperature to 3 degrees, but instead avoids turning into a popsicle. If you bring her into contact with snow, she freezes solid—which kills her.

Other insects can even get cooler: the ribbed pine borer, or the beetle Rhagium inquisitor, can supercool to minus 24 degrees. Now we ask, is a supercooled Arctic ground squirrel in danger of freezing solid? It is possible, but highly unlikely. Its skin should be pierced first by an icicle or something like that.

References:

Suspended Animation by Robert W. Prehoda, chapter 3

Hygienic System by Herbert M. Shelton, Vol. III  

Animal life at Low Temperature by John Davenport

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