| Question:
Since almost everything on a duck or goose is covered with feathers, except for the feet, how do they keep them warm, or from freezing?
Daryl Rodgers
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Answer:
Since the featherless portion of a duck’s leg and foot contains very little muscle, the main issue is maintaining the ducks core body temperature under cold conditions. Since a duck’s legs are in direct contact with either ice or very cold water, you can imagine the potential for an extreme loss of body heat. The mechanism present in a duck’s leg that prevents such heat loss is called countercurrent heat exchange.
In review, arteries carry oxygen rich blood away from the heart and throughout the body. Veins in turn carry the oxygen depleted blood back to the heart. In the legs of ducks (and other birds), arteries and veins run parallel and in contact with each other. As the warm blood of the arteries enters the legs, the heat is actually transferred to the returning cold blood of the veins. During extremely cold conditions, just enough blood is allowed to enter the leg to prevent freezing. Under very warm conditions, the countercurrent heat exchange mechanism can be bypassed and blood is allowed to flow directly into the extremities; thereby, allowing for rapid heat loss.
Next time you are in the duck blind on a cold fall or winter day, you can impress your duck hunting partners with this tidbit of information.
Good luck and safe hunting!
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