During torpor, the hummingbird’s body temperature can drop almost 50 degrees. The heart rate may slow from 500 beats per minute to fewer than 50, and breathing may briefly stop. A hummingbird consumes as much as 50 times more energy when awake than when torpid.
How do hummingbirds come out of torpor? As their heart and breathing rates rise, they start vibrating their wings. The heat generated by the vibrating wings warms the blood supply. The warmed blood circulates throughout the tiny bird’s body, and soon the hummer’s body temperature is back up to its normal, toasty 102.2 degrees.