A polar bear in the arctic maintains a steady body temperature despite the fact that environmental temperature plummets to extreme low during winter. How is this made possible?
1 Answer
Apr 13, 2017
Polar bear is a mammal; the vertebrate class is characterised by its ability to maintain a steady internal body temperature irrespective of temperature of the outside environment. Such animals are called homoeothermic.
Explanation:
Warm body temperature of bear is maintained by an intrinsic process, called thermoregulation :- a complex homeoststic process controlled by hypothalamus of brain. As temperature is maintained by internal generation, this organism is called endothermic.
Polar bear is able to maintain the body temperature at 37 degree C, by generating a lot of metabolic heat even when the polar temperature goes below
- Metabolic rate is very high in polar mammals to maintain warm body temperature.
- Heat loss is minimum in polar bear due to relatively less surface area, compared to a large body. Vasoconstriction in skin prevents heat loss.
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- Interestingly, their skin is black in colour despite having a thick white fur. Black skin is better in absorbing solar radiation during summer.
- There are two types of hairs to trap body heat: long guard hairs and small dense underfur.
- Very thick layer of subcutaneous fat gets deposited in their body as the winter approaches. It acts as superb insulating material.
- In winter, female polar bear remains within a closed ice chamber (either pregnant/with cubs) where temperature is maintained by its own body heat.
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