In the winter, their metabolism slows bears more than can be predicted by their body temperature.

Do not judge a bear of body temperature, such as indicated by the first data on the physiology of hibernation.

There's something that happens to a black bear hibernation that slows metabolic ratio was more than could be explained by a low body temperature, according to the report Øivind Tøien ecological physiologists from the University of Alaska Fairbanks.

In the winter of Alaska, the black bear closely monitored, lowering their body temperature an average of only 5.5 degrees Celsius, as reported by Tøien and his colleagues in the February 18 issue of the journal Science. Calculations predict that the physiological standard cold as it will slow down the metabolism of about 65 percent ratio nonhibernasi break. However, your metabolism slows down even the bears is to zone the energy savings on average only 25 percent of the basic ratios summer.

Things like that have so far not been found in studies in other mammals that hibernate, said co-researcher Brian M. Barnes is also from the University of Alaska Fairbanks.

Mammalian hibernation is important for human medical research, said ecologist Hank Harlow physiologist from the University of Wyoming in Laramie. By basing on the mechanism that would love to be understood by scientists, black bears spend five to seven months without eating, drinking or urination. But not like people who just spend time in bed or space, mammals that hibernate do not lose muscle strength or their bone mass. "Bear is awesome," said Harlow.

This is the first study that continuously monitors the ratio of metabolism and body temperature during hibernation bears on the conditions of low disturbance, said Tøien. Other studies based sampling is not continuous with the older equipment, circumstantial evidence, or study the bears with a lot of people who are in close proximity, produces "uncertainty," he said.

He and his colleagues get the amount of data in such a way to volunteer for the study of black bears are looking for food near residential areas and will soon be killed because it is considered as a threat. "We read about them in the Anchorage Daily News before we get them," said Tøien.

For their hibernation study, the researchers monitored five bears, placing them in wooden boxes deep in the forest. Wooden boxes are deliberately made not too strong so that the bears can destroy it whenever they want to come out. But when the Bears were in it, the researchers examined the oxygen concentration to track metabolic ratio. The instruments also measure muscle movement and function of the heart.

One of the bears was not much lower body temperature during early hibernation until she gave birth to a baby bear. The cubs do not survive, and after that the body temperature of the female polar bears bodies behave more like other bears.

Reports on the decline in the ratio was pretty good metabolism during hibernation encouraging Eric Hellgren of Northern Illinois University, which recognizes "a biased viewpoint as a bear biologist." He said a study conducted in Alaska will probably end the lengthy discussion that considers physiologists bear hibernation as "a form different and 'more for less'" compared with the metabolic changes seen in small animals such as ground squirrels.

More detailed monitoring also revealed specific habits other bears, such as cycles or semingu few days during mid-hibernation when the bears to temporarily raise their body temperature. Tøien not assess small increase is equivalent to the periodic warming of the full common to almost all the smaller animals that do hibernate, which raise their body temperature to normal within a few weeks, urinate and then lowered their body temperature. The researchers are not careful measuring metabolism during bear cycles will get the inflation rate on the line of hibernation, he noted.

Measurement of heart rate on the three bears of Alaska showed a decrease from an average of 55 beats per minute before hibernation to 14 beats per minute erratic dinin season. Harlow said that he too had heard the heart beat bears hibernating for a while and then clocked uncertain. Perhaps to save energy, speculation.

Alaska team also found that when the bears move again in the spring, their metabolism takes several weeks to crawl back to normal. Monitoring data showed that bears a metabolic half-speed ratio is still showing normal bear behavior.

Observation fits with studies conducted on grizzly bears that spend the first few weeks after hibernation with half a heart rate of speed at the time of the summer, said Lynne Nelson of Washington State University in Pullman. "Adaptability physiological systems bears this never stops surprising me."

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