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:
“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)
“Beauty sat bathing by a spring,
Where fairest shades did hide her;
The winds blew calm, the birds did sing,
The cool streams ran beside her.
My wanton thoughts enticed mine eye
To see what was forbidden:
But better memory said Fie;
So vain desire was chidden—”
—Anthony Munday (1553–1633)
“When you have shot one bird flying you have shot all birds flying. They are all different and they fly in different ways but the sensation is the same and the last one is as good as the first.”
—Ernest Hemingway (1899–1961)