Birds
In birds with webbed feet, retia mirabilia in the legs and feet transfer heat from the outgoing (hot) blood in the arteries to the incoming (cold) blood in the veins. The effect of this biological heat exchanger is that the internal temperature of the feet is much closer to the ambient temperature, thus reducing heat loss. Penguins have them also in the flippers and nasal passages.
Read more about this topic: Rete Mirabile
Famous quotes containing the word birds:
“What a fog! Plane been buzzin’ around overhead for the last half hour. Must be like trying to find your way through the inside of a cow. I never did see such a country. Even the birds are walkin’.”
—Dalton Trumbo (1905–1976)
“And as he sowed, some seed fell on the path, and the birds came and ate it up.”
—Bible: New Testament, Mark 4:4.
“Thou waitest late and com’st alone,
When woods are bare and birds are flown,”
—William Cullen Bryant (1794–1878)