The Hummingbird Heart Rate is Unbelievably Fast

The Hummingbird Handbook provides an answer and additional interesting information about these tiny birds' hearts. “Hummingbirds have the largest hearts per animal. John Shewey writes that their hearts weigh 2.5% of their body weight.  

“For context, the heart makes up only 0.3% of body mass. Hummingbirds have amazing heartbeats, 500 to 1,200 per minute, depending on activity. In contrast, humans rest at 72 beats per minute.

Ruby-throats' hearts race when they fly hard. That rate drops in calmer times. Though you may not notice it at your feeders, hummingbirds spend much of their day perching or resting.

Torpor also alters numbers. If the bird is resting or conserving energy on a cold night, its heart rate may decrease to 50 beats per minute. Up to 95% slower metabolism.

High heart rate means high energy burn. The Journey North research team at the University of Wisconsin-Madison found that ruby-throated hummingbirds have the fastest metabolisms in birds and animals. They can consume three times their weight in nectar daily.

The San Diego Zoo estimates hummingbirds need 3–8 calories daily. It seems unimportant at first. But that would involve eating 155,000 calories a day.  

Hummingbirds must digest swiftly due to their large diets. In 15 minutes, they can digest a spider 70 times faster than us.

If our bodies were as fast as hummingbirds', we would need to eat over 300 quarter-pound cheeseburgers per day.