Photo: Heron masters the one-leg pose

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Our photo of the day is a lesson in heat conservation.

Have you ever wondered why some birds stand on one leg? This photo of a great blue heron, taken by KennyTheKoala, is a beautiful example of the stance. (The way that raised foot is held so delicately, what elegance!)

BirdNote explains that the graceful balancing act is all about keeping warm. They write:

"Birds' legs have an adaptation called 'rete mirabile' that minimizes heat loss. The arteries that transport warm blood into the legs lie in contact with the veins that return colder blood to the bird's heart. The arteries warm the veins. Because the veins also cool the arteries, the bird’s feet are closer to environmental temperature and thus don’t lose as much heat as they would if they were at body temperature. And by standing on one leg, a bird reduces by half the amount of heat lost through unfeathered limbs."

Would you like to see your nature photo featured as the TreeHugger photo of the day? Join TreeHugger’s Reader Photo Pool on Flickr and add your pictures to the group. Alternatively, send it to with "photo of the day" in the subject line.

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