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 sea was wet as wet could be,
The sands were dry as dry.
You could not see a cloud, because
No cloud was in the sky:
No birds were flying overhead—
There were no birds to fly.”
—Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)
“And as he sowed, some seed fell on the path, and the birds came and ate it up.”
—Bible: New Testament, Mark 4:4.
“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)