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:
“These beginnings of commerce on a lake in the wilderness are very interesting,—these larger white birds that come to keep company with the gulls.”
—Henry David Thoreau (1817–1862)
“May! Be thou never graced with birds that sing,
Nor Flora’s pride!
In thee all flowers and roses spring,
Mine only died.”
—William Browne (1591–1643)
“Thou waitest late and com’st alone,
When woods are bare and birds are flown,”
—William Cullen Bryant (1794–1878)