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:
“I would that we were, my beloved, white birds on the foam of the sea!
We tire of the flame of the meteor, before it can fade and flee;
And the flame of the blue star of twilight, hung low on the rim of the sky,
Has awaked in our hearts, my beloved, a sadness that may not die.”
—William Butler Yeats (1865–1939)
“In a herber green, asleep where I lay,
The birds sang sweet in the mids of the day;
I dreamed fast of mirth and play.
In youth is pleasure, in youth is pleasure.”
—Robert Wever (fl. C. 1550)
“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)