Hummingbirds use a huge amount of energy. Just by sleeping, a hummingbird can lose 10% of its body weight in one night. To save energy when it is very cold outside or if they did not find enough food during the day to get them through the night, they may go into torpor. Similar to hibernation, they can lower their body temperature and heart rate, so they use up to 50 times less energy than when awake.     Back to Red Rufous Section