2006-10-06 03:29:23 · 11 answers · asked by Ian D 1 in Science & Mathematics ➔ Zoology
Penguins have specially adapted blood vessels in their feet to help them cope with standing on cold ice.
The blood vessels supply just enough heat to prevent the penguins freezing to the ice, while at the same time keeping the heat loss to a minimum. The blood vessels carrying warm blood to the feet are intertwined with those carrying the cold blood back from the feet - in this way the returning blood is warmed and that going to the feet is cooled - thus reducing the overall heat loss.
2006-10-06 03:32:50 · answer #1 · answered by Anonymous · 1⤊ 1⤋
A very good question.
The short answer is that birds have a mechanism in their legs known as "counter-current circulation". This allows their bodies to stay warm without losing too much body heat to the colder environment.
The average body temperature of a bird is close (if not a bit higher) than that of mammals. When blood is pumped from the heart to the rest of the body, the blood is at body temperature. There is a danger, however, that when the blood reaches the feet, most of the body heat that the blood is carrying will be transferred out to the colder air. If this were allowed to continue, the animal would eventually freeze to death (or, it would have to expend a *lot* of metabolic energy just to keep warm).
How birds, such as penguins, prevent this is by transferring their body heat from an artery (which is bringing the warmed blood to the feet) to a vein (which brings the warmed blood back to the body). This allows the blood to reach the feet and oxygenate the tissues, but reduces the amount of body heat lost to the environment. In this manner, the animal can stay warm.
How is heat transferred from an artery to a vein? The artery bringing blood down the legs to the toes is literally surrounded by a number of veins. The blood in the veins is cooler than the blood in the arteries, so a thermal gradient is established, allowing the heat to be transferred via convection (convection = physical transfer of heat). The temperature of the blood at the bird's foot is considerably lower than the temperature of the blood back near the heart; but it is still above freezing temperatures.
Why this isn't uncomfortable for a bird, I don't know, but there you go!
Hope that helps!
2006-10-09 09:32:42 · answer #2 · answered by red_iguana27 2 · 0⤊ 0⤋
penguins are immune to the cold, even if you sat it in tha freezer for say five years it still would not freeze. (though it would be very lonley without a mate lol)
2006-10-06 12:16:40 · answer #3 · answered by jacorvisc 2 · 0⤊ 0⤋
All down to Mother Nature, think about it?
2006-10-06 10:46:57 · answer #4 · answered by ? 6 · 0⤊ 0⤋
penguin polar booties :)
2006-10-06 16:14:15 · answer #5 · answered by stuckinthestargate 4 · 0⤊ 0⤋
lol that's a good question
i am guessing because they are use to it
and they were designed like that.
2006-10-06 10:32:59 · answer #6 · answered by XxXxPinkPrincessxXxX 3 · 0⤊ 0⤋
Because they stand on their heads when nobody is looking.
2006-10-06 10:34:41 · answer #7 · answered by MI5 4 · 0⤊ 0⤋
My granny spends all her spare time knitting them socks!
2006-10-06 10:36:44 · answer #8 · answered by mommakayos 2 · 0⤊ 1⤋
because they have insulation on them.
2006-10-06 10:36:43 · answer #9 · answered by ballmonkeyhockey 5 · 0⤊ 0⤋
becauze they can fill them
2006-10-06 10:31:50 · answer #10 · answered by HOT BUT SEXY 1 · 0⤊ 0⤋