Explain why perennial aquatic mammals (whales, dolphins) have much more powerful insulating covers

Explain why perennial aquatic mammals (whales, dolphins) have much more powerful insulating covers (subcutaneous fat) than terrestrial animals living in harsh and cold conditions. For comparison: the temperature of salt water does not drop below -1.3 ° C, and on the surface of land it can drop to -70 ° C.)

water has a significantly higher thermal conductivity and heat capacity than air. A warm object in water will cool down (give off heat) much faster than in air.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.