The Act of Deep Sleep

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Whenever somebody learnt that I was moving to Canberra they were very quick to warn me that Canberra got very, very cold. It was the first comment they made, and it was usually accompanied by laughter. Coming from a notoriously cold place myself, I will admit I took this warning with a rather large cup of scepticism and a sprinkle of disbelief. However, here we are in July: big coats, gloves, scarves and a multitude of beanies as far as the eye can see. All this, coupled with the frosted cars in the car parks and the lovely headline ‘Canberra weather: Colder than Thredbo on Monday morning’. I cannot deny it any longer; Canberra gets very, very cold. The struggle to climb out of the covers every morning into the chilly air is perhaps what put the final nail in the coffin so to speak, as I admit I have found myself wishing I could hibernate.

‘Hibernation’ is the act of spending the winter in a dormant condition typically performed by various animals and plants.

Without a doubt, the most famous of all hibernators is the bear. This is most likely due to them featuring in stories wherein the hero/heroine/team must sneak past to grab an object in the bear’s possession without awakening it, lest it should eat them. Ironically this little detail – without awakening them – tells us that bears are in fact not true hibernators, but rather light hibernators who ‘torpor’.

True hibernators and light hibernators, torpor and hibernate: what’s the difference?

Hibernation is like a deep sleep from which it is difficult to wake (which I’m sure our hero/heroine/team would prefer over an easily awoken bear). During true hibernation an animal’s body temperature is lowered and their breathing and heart beat are slowed in order to conserve energy. Depending upon the species this state can last from several days to months. Torpor, like, hibernation includes the lowering of body temperature, breathing and heart rate, however, it is different in that it either lasts for short periods of time, or the animal’s body temperature remains high enough so that it can wake quickly. Some animals, like Deer Mice, torpor daily.

Every animal hibernates differently. Wood Frogs, for example, actually stop breathing – their heart stops, ice crystals form in their blood, and thus these creatures appear dead to the rest of the world. That is, until it warms up again and they, well, they defrost. Just about all other animals that hibernate or torpor, however, will wake briefly to feed and take care of other needs. Some animals, such as hamsters, will only torpor if there is a supply of food nearby.

There is one notable exception to this rule – the famous bear – who will not eat, drink or excrete at all whilst hibernating for up to six months. Interestingly though, female bears can give birth and nurse their young during torpor.

In addition to this, if you thought that hibernation only takes place in winter, you can think again! Aestivation, occurring in summer in response to heat stress, typically occurs in cold-blooded animals such as lungfish, crocodiles or even the common Poorwills (the only bird that is a true hibernator, but can also aestivate).

So, given Canberra’s lovely, cheery weather looks set to continue for some time, the temptation to attempt hibernation – or more likely torpor – until warmer temperatures return to us, for me at least will continue.