In the cold winter it is hard to find food, and to maintain body temperature it is necessary to eat a lot. This is why bats in temperate regions depend on going into hibernation for the winter.
嚴冬萬物蟄伏，不易覓食，為維持體溫，又必須大量捕食，溫帶地區的蝙蝠就靠冬眠捱過冬季。