Step 1: Understanding the Concept
Animals facing harsh conditions can migrate, or stay and escape the stress in time.
Step 2: In winter
Animals that cannot migrate, such as bears and bats, lower their metabolism and spend winter in a sleep-like state called hibernation.
Step 3: Other terms
Aestivation is summer inactivity to avoid heat and drought. Dormancy is a general term.
Final Answer:
Such animals go into hibernation during winter.
\[ \boxed{\text{(B) }\text{Hibernation}} \]