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:
“One ought not to have to care
So much as you and I
Care when the birds come round the house
To seem to say good-by;”
—Robert Frost (1874–1963)
“We can never see Christianity from the catechism:Mfrom the pastures, from a boat in the pond, from amidst the songs of wood- birds we possibly may.”
—Ralph Waldo Emerson (1803–1882)
“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,”
—Henry Vaughan (1622–1695)