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:
“She does the work about the house
As well as most, but like a mouse:
Happy enough to chat and play
With birds and rabbits and such as they,
So long as men-folk keep away.”
—Charlotte Mew (1870–1928)
“Chaucer is fresh and modern still, and no dust settles on his true passages. It lightens along the line, and we are reminded that flowers have bloomed, and birds sung, and hearts beaten in England. Before the earnest gaze of the reader, the rust and moss of time gradually drop off, and the original green life is revealed. He was a homely and domestic man, and did breathe quite as modern men do.”
—Henry David Thoreau (1817–1862)
“Birds which are the same color as the foliage in which they nest are less likely to be disturbed by other birds who want to drop in and chat, and therefore last longer.”
—Robert Benchley (1889–1945)