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:
“Thou waitest late and com’st alone,
When woods are bare and birds are flown,”
—William Cullen Bryant (1794–1878)
“The sun, the hero of every day, the impersonal old man that beams as brightly on death as on birth, came up every morning and raced across the blue dome and dipped into the sea of fire every evening. Water ran down hill and birds nested.”
—Zora Neale Hurston (1891–1960)
“We must not make a scarecrow of the law,
Setting it up to fear the birds of prey,
And let it keep one shape, till custom make it
Their perch and not their terror.”
—William Shakespeare (1564–1616)