Natures Wonders: torpor (Introduction)

by David Turell , Wednesday, December 30, 2020, 19:39 (1424 days ago) @ David Turell

Not quite hibernation:

https://phys.org/news/2020-12-torpor-neat-survival-thought-rare.html

"Life is hard for small animals in the wild, but they have many solutions to the challenges of their environment. One of the most fascinating of these strategies is torpor. Not, to be confused with sleep or Sunday afternoon lethargy, torpor is a complex response to the costs of living.

"To enter torpor, an animal decreases its metabolism, reducing its energy requirements. A torpid animal will often be curled in a tight ball in its nest and look like it's sleeping.

"Once thought to occur only in birds and mammals in the Northern Hemisphere where winters are more pronounced, we now know torpor is widespread in small Australian mammals, and has also been observed in many small Australian bird species.

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"With a lower metabolic rate, the animal's body temperature decreases—sometimes by as much as 30°C. How low it goes can depend on the extent of the metabolic reduction and the temperature of animal's immediate environment. The reduced body temperature further lowers the metabolic rate.

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"Many pregnant and lactating bats and marsupials, and even the echidna, synchronise torpor with reproduction to cope with the energetic costs of mating, pregnancy or lactation.

There are two main types of torpor: daily torpor and hibernation.

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"Animals that hibernate lower their metabolic rate further and have longer torpor bouts than those that use daily torpor. An example of an Australian hibernator is the eastern pygmy possum, a 40g marsupial found in south eastern Australia that hibernates regularly, decreasing its body temperature from approximately 35 °C to as low as 5°C.

"When active, this species can survive for less than half a day on 1g of fat, but when hibernating, it can survive for two weeks.

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"The question people often ask about torpor, is "can humans do it?" Interestingly, some small primates have been observed using torpor. While it is technically possible to induce torpor in humans chemically, torpor is a very complex physiological process, and there are many aspects of it scientists still don't fully understand."

Comment: The final comment above suggests that this process would be hard to evolve naturally. It is such an integrated and convoluted physiological process involving multiple alterations in metabolism, it must have been designed by God to have this degree of convergence in evolution.