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:
“... to a poet, the human community is like the community of birds to a bird, singing to each other. Love is one of the reasons we are singing to one another, love of language itself, love of sound, love of singing itself, and love of the other birds.”
—Sharon Olds (b. 1942)
“Yet this aboundant issue seem’d to me,
But hope of Orphans, and un-fathered fruite,
For sommer and his pleasures waite on thee,
And thou away, the very birds are mute.
Or if they sing, tis with so dull a cheere.
That leaves looke pale, dreading the winter’s neere.”
—William Shakespeare (1564–1616)
“It would be well, perhaps, if we were to spend more of our days and nights without any obstruction between us and the celestial bodies.... Birds do not sing in caves, nor do doves cherish their innocence in dovecots.”
—Henry David Thoreau (1817–1862)