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:
“So near to paradise all pairing ends:
Here loveless birds now flock as winter friends,
Content with bud-inspecting. They presume
To say which buds are leaf and which are bloom.”
—Robert Frost (1874–1963)
“Thou waitest late and com’st alone,
When woods are bare and birds are flown,”
—William Cullen Bryant (1794–1878)
“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)