Hibernation: New Study Reveals Many Interesting New Things About It
Posted: Sunday, February 20, 2011
by Joel Hendon
http://hebronics.org/index.html
Have you ever wished you could just hibernate the frigid, dreary days of winter away? A number of animals do that and scientists have recently concluded a most comprehensive study of it. According to a BBS news article, five bears have been the subject of the most detailed hibernation study ever undertaken in animals of their size.
Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate. It is the animal's slowed metabolic rate which leads to a reduction in body temperature and not the other way around. (Wikipedia: Hibernation)
Researchers from the American Association for the Advancement of Science (AAAS) reported the bears metabolism rate dropped to 25% of it’s normal level. They have determined that the drop in metabolism is the factor which controls the other factors, drop in temperature, heart rate and breathing rates, etc. (Mother bear and cubs hibernating-Wikipedia photo)
One rather interesting fact according to their findings is that there is a direct correlation between the metabolism. When the metabolism reduces by half, body temperature drops 10 degrees Celsius. This factor cause them to believe they are both results of the same mechanism.
The bears lowest temperatures were approximately 31 °C (88 °F). At this point, their breathing and other metabolism factors reached a mere 25% of normal. When they reached this low level, they would begin to shiver, which in turn, brought their temperature up to nearly normal over a period of several days during these cycles. Their normal body temperature is 38 °C (100.4 °F)
"The bears typically during hibernation will take a deep breath and exhale and when they do, their heart stops and doesn't beat at all for 10, 15, 20 seconds," said Brian Barnes, the Institute of Arctic Biology researcher who led the study.
"They held their breath for about a minute, and it's only when they inhale again that their heart picks up," he told BBC News. "It's just this alternative way of being that's very spare, that we didn't know was possible, particularly in large animals." (Hibernating bears studied in unprecedented detail-BBC News-Jason Palmer)
These bears being studied were in captivity. They were wild but became “nuisance bears” in that they were coming into residential areas. In captivity, they were exposed to their normal climate exposure in manufactured “dens” with straw bedding. They had implanted chips which gave readings of their vital signs. It is reported that they, about daily would awaken enough to “fluff” their bedding.
Also an apparently unexpected phenomenon was when they awakened from their hibernation, and their body temperature rose to normal, about 38C, their metabolism remained low, at about half normal for up to three weeks. This factor, it seems, would place a question mark upon their supposition that the two factors were by the same mechanism as they assumed when they went into hibernation.
Scientists are excited over their findings, hoping to discover some method of inducing the lowering of human metabolism which might be extremely important where one is sick or injured but with insufficient strength to be transported to some distant point for care.
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