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:
“man also knoweth not his time: as the fishes that are taken in an
evil net, and as the birds that are caught in the snare; so are the
sons of men snared in an evil time,”
—Bible: Hebrew Ecclesiastes (l. IX, 12)
“Even Lust the Master of a hardned Face,
Blushes if thou beest in the place,
To darkness’ Curtains he retires,
In Sympathizing Night he rowls his smoaky Fires.
When, Goddess, thou liftst up thy wakened Head,
Out of the Mornings purple bed,
Thy Quire of Birds about thee play,
And all the joyful world salutes the rising day.”
—Abraham Cowley (1618–1667)
“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)