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)
“Weighing the steadfastness and state
Of some mean things which here below reside,
Where birds like watchful clocks the noiseless date
And intercourse of times divide,”
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“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)