The long winter sleep is known as Hibernation. The word “hibernation” is derived from the Latin word 'hibernare', meaning, “to pass the winter”. Animals like Polar Bears went for hibernation which helps them to survive the changing seasons.

What is long sleep in winter called?

So, the correct answer is 'Hibernation'.

Which animal is long winter sleep?

It's no secret that bears hibernate during the winter. American black bears are hibernating champs, able to bed down for as long as 100 days. During this time the bear goes without eating, drinking, exercise or bathroom breaks.