Hummingbird Metabolism

Hummingbirds are energy dynamos. A 10-gram bird uses ten times as much oxygen per gram of body weight as does a human being. Hummingbird metabolism is amazing.

The smallest hummingbird weighs only 2.5 grams (less than a US penny). Their wings beat at about 50 times per second. Humans can hear sounds at that frequency, and the humming sound is what gives the birds their name. Their hearts can beat at 1200 times per minute which is ten times the highest rate of a human heart during heavy exercise. They breathe 250 times per minute.

Hummingbird metabolism requires that they consume more than their weight in nectar each day. To eat, they have to hover using energy at an incredible rate, and they are always only a few hours from starving to death. At the rate a hummingbird burns energy during the day, it would not have enough to survive overnight, so it goes into a state called torpor. Torpor reduces body temperature and reduces hummingbird metabolism to one-fifteenth of its normal rate.

Coming out of torpor means the bird needs time to wake up in the morning. It may take up to twenty minutes to bring the body temperature back to daytime levels. There are many design features in the hummingbird that make the wake-up process possible.

As cold weather approaches, the ruby-throated hummingbird will bulk up, doubling its weight to make an 800 km (500 mi) non-stop flight from the USA across the Gulf of Mexico to warmer climates.The fact that this tiny bird can survive is a demonstration of the incredible plan of a Master Designer.
© Roland Earnst

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