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:
“The birds their quire apply; airs, vernal airs,
Breathing the smell of field and grove, attune
The trembling leaves, while universal Pan,
Knit with the Graces and the Hours in dance,
Led on th’ eternal Spring.”
—John Milton (1608–1674)
“Let us not succumb to nature. We will marshall the clouds and restrain tempests; we will bottle up pestilent exhalations; we will probe for earthquakes, grub them up, and give vent to the dangerous gas; we will disembowel the volcano, and extract its poison, take its seed out. We will wash water, and warm fire, and cool ice, and underprop the earth. We will teach birds to fly, and fishes to swim, and ruminants to chew the cud. It is time we looked into these things.”
—Henry David Thoreau (1817–1862)
“The kiss of the sun for pardon,
The song of the birds for mirth,
One is nearer God’s Heart in a garden
Than anywhere else on earth.”
—Dorothy Frances Gurney (1858–1932)