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:
“We cannot do without it, and yet we disgrace and vilify the same. It may be compared to a cage, the birds without despair to get in, and those within despair to get out.”
—Michel de Montaigne (1533–1592)
“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)
“Chaucer is fresh and modern still, and no dust settles on his true passages. It lightens along the line, and we are reminded that flowers have bloomed, and birds sung, and hearts beaten in England. Before the earnest gaze of the reader, the rust and moss of time gradually drop off, and the original green life is revealed. He was a homely and domestic man, and did breathe quite as modern men do.”
—Henry David Thoreau (1817–1862)