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:
“The air deals blows: surely too hard, too often?
No: it is bent on bringing summer down.
Dead leaves desert in thousands, outwards, upwards,
Numerous as birds; but the birds fly away....”
—Philip Larkin (1922–1986)
“In almost all climes the tortoise and the frog are among the precursors and heralds of this season, and birds fly with song and glancing plumage, and plants spring and bloom, and winds blow, to correct this slight oscillation of the poles and preserve the equilibrium of nature.”
—Henry David Thoreau (1817–1862)
“poems direct as what the birds said,
hard as a floor, sound as a bench,
mysterious as the silence when the tailor
would pause with his needle in the air.”
—Denise Levertov (b. 1923)