"…Brown adipose tissue (BAT) is a fat storage tissue especially abundant in small mammals and newborn humans. BAT is highly vascularised, full of mitochondria and burns fat to produce heat in a special way. Maybe it could provide the warmth the rodents require to survive winter in addition to its supposed role in arousal?
The team found that the BAT of cold acclimated rats took up fatty acids that were oxidised to generate heat. Amazingly, these rats were up to 12 times better at the conversion than the other rats. Additionally, while the other rats slowed their ventilation, the cold acclimated rats increased their breathing rate to better supply BAT with oxygenated blood and hence maintain their temperature while being cooled.The authors decided that BAT is the true 'thermogenic machinery' for non-hibernators…Scientists think BAT fat metabolism that non-hibernators use to stay warm and remain alert during cold conditions may have been one key to the evolutionary success of early mammals." (Rummer 2010:vi)