Britannica
Sources used in this answer
How do brown fat and white fat help hibernating animals?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
Dormancy
Virginia big-eared bats (Corynorhinus townsendii virginianushibernating) are true hibernators, entering a state close to death for much of the winter.
In hibernating animals, white and brown adipose tissue serve distinct but essential roles in survival:
- White Adipose Tissue: This tissue functions primarily as a vital energy reservoir. Hibernating animals often accumulate significant fat deposits before entering dormancy, which are then mobilized to provide the necessary fuel to maintain the animal's metabolism at a minimal level throughout the winter. Additionally, white adipose tissue provides thermal insulation, helping the animal conserve body heat.12
- Brown Adipose Tissue: Unlike white fat, brown adipose tissue is specialized for heat production through a process called nonshivering thermogenesis. It contains a high density of mitochondria and a protein called thermogenin (UCP1), which allows the cells to uncouple energy production from ATP synthesis, causing energy to be released as heat instead. This mechanism is crucial for hibernating animals, particularly during the dangerous and energy-intensive periods of arousal from hibernation, when the animal must rapidly generate heat to restore its body temperature.321