Why don’t seals “Shiver” in the water

Seals “Shiver” on dry and cold land, but feel at ease in biting cold water. For decades, scientists have been interested in this strange phenomenon. Studying it can further understand how human beings live in low temperature and hypoxia.

Lars falkou, a researcher at Tromso University in Norway, recently reported at the general meeting of the American Physiological Association that seals “Shiver” on land to keep their body temperature; No longer “shivering” in the water. Although the body temperature drops, it reduces metabolism and oxygen consumption, so that it can dive deep for a long time and facilitate predation.

The online edition of the British magazine Nature reported on the 10th that Falkow and others put 12 seals into a special device to measure their heart rate and body temperature changes in different environments. The results showed that when the device was placed on water and the room temperature fell to minus 35 ℃, the seal trembled violently; But when the device was immersed in cold salt water, these marine mammals immediately stopped “shivering”.

Falkou believes that for warm blooded animals that need to maintain a certain body temperature to survive, the practice of seals not “shivering” in the water is not good. But it’s worth freezing to stay underwater for a long time to catch prey and have a good meal.

Falkou also found that in the water, the seal’s brain temperature can be reduced by 3 degrees Celsius in a quarter of an hour, and the heart rate can be reduced from 90 beats per minute to 10 beats per minute, which reduces oxygen consumption and brain damage during deep diving. He said that seals are more tolerant to hypoxia than humans. Studying the mechanism will enable people to better understand the situation of human brain hypoxia during heart attacks, so as to help develop targeted therapies.

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