Gimme Shelter

But antifreeze may also work quite well

As a member of several Antarctic expeditions of my university and the leader of Jamaica’s first (and only) Antarctic research trip in 1993, I was naturally concerned with the clothes we had to take along to keep us warm there. But the question that also arose in a situation like this was, how do organisms, generally, cope with the intense cold that occurs at high latitude or high altitude regions?

If you are a warm-blooded, endothermic, animal, you have less of a problem than a cold-blooded, ectothermic creature, for you can generate your own heat – provided of course you have the “fuel” for your body furnaces to burn and turn into inner warmth. Poor Robert Falcon Scott and his men, after having reached the South Pole on January 17, 1912 one month after being beaten by the Norwegian Roald Amundsen, simply did not have sufficient calorific intake and died of cold, starvation and exhaustion on their return from the Pole to Base Camp. Amundsen, incidentally, disappeared 1928 in the Arctic with a search plane trying to rescue members of Italian Umberto Nobile’s ill-fated airship expedition to reach the North Pole.

As a warm-blooded creature, sure, you lose body heat to the cold environment, but if your body volume is not too small and you possess dense feathers, a thick coat of fur or an insulating layer of blubber/fat, you can feel warm nonetheless. After all, it’s easier to keep warm in the cold than it is to keep cool in the heat. Without some heat-conserving adaptations, however, there are only three other possibilities to survive in the cold. The first, used by both warm and cold-blooded animals, is to move away from the cold and to seek out sheltered places, to rest and conserve energy. Hibernation, sleeping the winter away, would be the best option, but it is not available to everyone and, for instance, sheltering in loose snow against an icy wind can only be maintained as long as the need to feed and search for food isn’t greater than the need for sheltering.

The two remaining methods apply to cold-blooded animals only: some insects like, to name but two, are the larvae of an Alaskan chironomid mosquito and the adults of a New Zealand mountain weta (a sort of huge cricket). They together with tiny bear-animalcules, some nematode worms and a few other microscopic organisms, for reasons often not yet fully understood in all detail, can tolerate total freezing of the tissue and will revive upon thawing. Fish, frogs, snakes and lizards, with very few exceptions, cannot come back to life if frozen stiff. The exceptions are the Siberian lizard Zootaca vivipara, which may survive in the frozen state a temperature down to -10°C, and the Siberian salamander Salamandrella keyserlingi that is known to survive even temperatures to at least -30°C.

Certain Antarctic fish species, whose eyes and vision I had studied while in Antarctica, are able to depress their tissue freezing point by a couple of degrees with the help of antifreeze molecules in their blood. The antifreeze substances, as Art DeVries has shown, consist of molecules which bind to and surround the first ice crystals in the blood, preventing them from combining with others and leading to the solidly frozen state. In very small invertebrates, cells of their bodies get rid of almost all of their watery content when it gets cold and what is then left of their cell interiors has so little water in it that freezing does not occur and the cells can not expand and burst as it gets colder (ice expands as it gets colder: the famous anomaly of water!).

So, antifreezes do work, but from my visits to Antarctic I know that our men and women there would argue that a bottle of whisky (and rum in the case of my Jamaican friends) would also be quite effective against freezing to death – but they are totally wrong, of course. Why? Think about it: what colour does your skin get after a drink of whisky, vodka, or high percentage rum and what does that indicate with regard to your body heat conservation?

winter stupid bees science

For more reading about cold stories, click here for “Is winter making us stupid?

© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2016.
Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to V.B Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com with appropriate and specific direction to the original content.

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