Naked Science Forum
Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: neilep on 19/01/2008 16:35:20
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Dearest Hibernationologists !
See these hibernating animals ?
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Nice eh ?....see how peaceful and non active they are ?
Say conditions arose that they did not need to hibernate !...would their lifepsan be shorter ?...Does Hibernation increase lifespan ? Hibernation does slow down the metabolic rate yes ?...does this also slow the aging process ?
whajafink ?
Neil
xxxxx
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Well, it stops you from freezing to death, or starving to death, in winter - that must be an increase in life span.
Some animals I believe will optionally hibernate, depending on how cold the winter is - I'm not sure if it makes a difference to life expectancy.
Ofcourse, one problem is that life expectancy in the wild is rarely down to old age - it is usually down to predation - when an animal gets old enough that it can't run very fast, then something catches it and eats it. Only very big animals (such as elephants, of blue whales) that are too big to be brought down, no matter how slow they are, might be able to avoid predation in old age, but they do not hibernate.
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your pictures - yawn- have made me-yawn- quite slee.....
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Thats a good question but assuming that everything slow down, I would think that in itself would add to lengthening life!
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Well, it stops you from freezing to death, or starving to death, in winter - that must be an increase in life span.
Some animals I believe will optionally hibernate, depending on how cold the winter is - I'm not sure if it makes a difference to life expectancy.
Ofcourse, one problem is that life expectancy in the wild is rarely down to old age - it is usually down to predation - when an animal gets old enough that it can't run very fast, then something catches it and eats it. Only very big animals (such as elephants, of blue whales) that are too big to be brought down, no matter how slow they are, might be able to avoid predation in old age, but they do not hibernate.
I'm just trying to imagine a herd of Elephants hibernating !...
Thanks You George...although I am aware of the nature of hibernation.....and setting aside the reasons why they hibernate....I was wondering if the very act of hibernation in itself, slows down the aging process.....
....Assuming all circumstances being equal and there being an abundance of food and no predation....would an animal that hibernates live longer than it's counterpart that did not ?....even though there be no need hibernation !
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I think heart rate slows during hibernation and I do believe that would have the effect of slowing down that aging process as it should allow the heart to strain less etc. Perhaps the body produce and expend less energy and thus slow down growth etc.. also. I could be wrong.. perhaps hypothetically it could be compared to a stasis..of some type.. I believe they are trying to do something like that now for space travel... I heard about some study of hibernating animals to see if it could be induced in humans for space travel.. I don't know how much fact was in that as I heard it in flipping through tv chanels.. LOL..
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Slowing the metabolic rate should slow the rate of cell reproduction, so should extend lifetime.
You may already know this, so I'll put it here for those that don't, but DNA has special repeated sections called Telomeres. During DNA replication, some of these get lost, not copied properly, or knocked off (in fact, they act as a 'buffer' - damage done to them doesn't affect the genes, but if they weren't there, the ends of the genes could get knocked off, with disastrous consequences). So if you have fewer cell divisions, and therefore less DNA replication, there will be less damage to the telomeres.
This should mean that the organism can live for longer, as there's less cumulative damage to the DNA.
It would be interesting to see if hibernating animals undergo the same number of cell divisions, just at a slower rate. I assume they would.
On a related note, most people don't realise that hibernating animals completely empty their digestive system before going into hibernation. It's easy to assume that they stuff themselves and then bed down, but the last thing they need is food rotting in their stomach!
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Firstly, it seems that there is quite a spectrum of hibernation, from very light torpor, possibly waking several times during the period, to a very deep hibernation.
http://en.wikipedia.org/wiki/Hibernation
One animal that some famously consider a hibernator is the bear, although bears do not go into "true hibernation". During a bear's winter sleep state, the degree of metabolic depression is much less than what is observed in smaller mammals. Many prefer to use the term "denning". The bear's body temperature remains relatively stable (depressed from 37 °C to approximately 31 °C) and it can be easily aroused. In contrast, hibernating ground squirrels may have core body temperatures as low as -2 °C. Some reptile species are said to brumate, or undergo brumation, but the connection to this phenomenon with hibernation is not clear.
Even arctic ground squirrels, which may have body temperatures as low as -2°C, are still about 4°C above the ambient temperature, and so must still be maintaining some active metabolism.
Another thing to bear in mind is that deep hibernation can mean the shutting down of the immune system, which means potential heightened risk of damage through uncontrolled infection.
Finally, hibernation is part of a process - in that the animal will build up fat reserves before going into hibernation, and when emerging from hibernation, it will be under severe stress from lack of nutrition, and will need to eat soon. How much the stresses of going into hibernation and coming out of hibernation might offset any benefit in terms of life expectancy for the period of hibernation, I have no idea (and no doubt will depend upon how long the period of hibernation is for).
One last aside:
http://en.wikipedia.org/wiki/Hibernation#Human_hibernation
Erika Nordby, a toddler of 13 months in Edmonton, Alberta, wandered outside her family home on February 23, 2001. The outside temperature was -24 °C (-11 °F). When she was found, her heart had stopped beating for two hours and her internal body temperature had fallen to 16 °C (61 °F). Other sources say there was a slow pulse of 30 beats per minute but no blood circulation when paramedics arrived. In either event she was clinically dead. She suffered severe frostbite, yet required no amputation and made a full recovery.
In October 2006, a Japanese man, Mitsutaka Uchikoshi, was believed to have been in a "denning"-like state for three weeks. He had fallen asleep on a snowy mountain and claimed he had only woken up after being discovered 23 days later; doctors who treated him believed his temperature had fallen to 22 °C (71 °F) during that period.
http://en.wikipedia.org/wiki/Hydrogen_sulfide#Induced_hibernation
In 2005 it was shown that mice can be put into a state of suspended animation by applying a low dosage of hydrogen sulfide (80 ppm H2S) in the air. The breathing rate of the animals sank from 120 to 10 breaths per minute and their temperature fell from 37 °C to 2 °C (98.6 °F to 35.6 °F) above ambient temperature (in effect, they had become cold-blooded). The mice survived this procedure for 6 hours and afterwards showed no negative health consequences.
Such a hibernation occurs naturally in many mammals and also in toads, but not in mice. (Mice can fall into a state called clinical torpor when food shortage occurs). If the H2S-induced hibernation can be made to work in humans, it could be useful in the emergency management of severely injured patients, and in the conservation of donated organs.
As mentioned above, hydrogen sulfide binds to cytochrome oxidase and thereby prevents oxygen from binding, which leads to the dramatic slowdown of metabolism. Animals and humans naturally produce some hydrogen sulfide in their body; researchers have proposed that the gas is used to regulate metabolic activity and body temperature, which would explain the above findings.
In 2006 it was shown that the blood pressure of mice treated in this fashion with hydrogen sulfide did not significantly decrease.
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http://en.wikipedia.org/wiki/Hibernation#Human_hibernation
Erika Nordby, a toddler of 13 months in Edmonton, Alberta, wandered outside her family home on February 23, 2001. The outside temperature was -24 °C (-11 °F). When she was found, her heart had stopped beating for two hours and her internal body temperature had fallen to 16 °C (61 °F). Other sources say there was a slow pulse of 30 beats per minute but no blood circulation when paramedics arrived. In either event she was clinically dead. She suffered severe frostbite, yet required no amputation and made a full recovery.
In October 2006, a Japanese man, Mitsutaka Uchikoshi, was believed to have been in a "denning"-like state for three weeks. He had fallen asleep on a snowy mountain and claimed he had only woken up after being discovered 23 days later; doctors who treated him believed his temperature had fallen to 22 °C (71 °F) during that period.[quote/]
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Sorry George the quote thingy is not working right! I had to do what neil did when it acted up last! And make two posts!
Wow!! George that is amazing.. I take it there was some unverified information regarding the time Mitsutaka Uchikoshi had spent out there on the Mountain, but regardless it was incredible. Those conditions with both of them and they survived.. incredible! Thanks George that is an incredible post, good information.. thanks.