Why can hibernating hedgehogs wake up in cold air, but frogs cant?

Although hedgehogs are warm-blooded animals, their ability to regulate temperature is not very efficient. However, when they are active, their body temperature remains within a certain range. Some measurements have shown that the body temperature of a hedgehog during activity ranges from 33.7°C to 35°C. During hibernation, their body temperature drops sharply, generally ranging from 1.8°C to 4.3°C, lowering to approximately the ambient temperature. With this decrease in body temperature, all life processes slow down significantly. The respiratory rate decreases from around 50 breaths per minute to 4-5 breaths per minute, and the overall metabolic rate slows down drastically. This allows hedgehogs to survive the cold and food scarcity of winter without eating or moving much. However, exposing them to cold air (below 4°C) can stimulate the production of a large amount of heat energy internally, rapidly raising their body temperature to maintain a constant temperature similar to before hibernation, around 35°C, causing them to awaken.

Frogs, on the other hand, are cold-blooded animals, meaning their body temperature changes with the surrounding environment and they cannot regulate it internally. Therefore, when the cold winter arrives and the temperature drops, their body temperature also decreases, making it difficult for them to maintain their normal activities. If they don’t find a place to hide, there is a risk of freezing to death. Therefore, they hibernate in water or soil. Since frogs lack the ability to regulate body temperature, they cannot tolerate extreme cold and cannot survive temperatures below zero. Experiments have shown that frogs begin to freeze internally when their body temperature drops to around -0.44°C. Therefore, placing hibernating frogs in cold air below 0°C not only fails to wake them up but also causes external freezing and internal organ freezing due to the extreme cold, ultimately resulting in the death of the frogs.