What is the critical function of the thick layer of blubber beneath the grey seal's fur?

Answer

Insulation against frigid water and energy storage

The blubber serves two vital purposes: providing insulation to maintain core temperature in cold water and storing energy reserves needed for long fasting periods during breeding or migration.

What is the critical function of the thick layer of blubber beneath the grey seal's fur?
animalmammalmarineadaptationseal