A Hummingbird's Heartbeat

There are times when a fact - in this example, read in last week's 'New Scientist' - sits up and slaps me in the face. According to an article about Andean hummingbirds, they are capable of lowering their body temperature to 4C in order to reduce heat loss during bitterly cold nights. This was interesting enough but the article added that a hummingbird's normal heart rate is over 1,000 beats per minute. My heart, when I'm not excited, seems to function at just  over 60. How on earth does a tiny, tiny organ like a hummingbird's heart manage to beat at that rate?

Our most recent encounters with hummingbirds were in British Columbia, Canada. The top picture is of a black-chinned hummingbird, the lower of a calliope hummingbird. I thought it was amazing enough that these two tiny scraps migrate thousands of miles each year to winter in the southern part of North America, but my mind would have been blown away had I know about the rate at which their hearts were beating.