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:
“He put before them another parable: “The kingdom of heaven is like a mustard seed that someone took and sowed in his field; it is the smallest of all the seeds, but when it has grown it is the greatest of shrubs and becomes a tree, so that the birds of the air come and make nests in its branches.””
—Bible: New Testament, Matthew 13:31,32.
“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)
“When you have shot one bird flying you have shot all birds flying. They are all different and they fly in different ways but the sensation is the same and the last one is as good as the first.”
—Ernest Hemingway (1899–1961)