2007-04-26 05:17:23 · 12 answers · asked by Anonymous in Pets ➔ Birds
. The system that stops a penguin's foot from freezing is very elaborate and sophisticated and employs two mechanisms.
The first one allows the penguin to control the rate of blood flowing to its feet by varying the diameter of arterial vessels supplying the blood. In cold conditions the flow is reduced, when it is warm the flow increases.
The second mechanism takes the form of 'counter current heat exchangers' at the top of the legs. The arteries, which supply warm blood and oxygen to the penguin's feet break up into many small vessels which are closely linked to similar numbers of venous vessels bringing cold blood back from the feet. So, when heat is lost from the arterial vessels, the venous vessels running in the opposite direction pick it up and carry it back through the body, rather than out through the feet. This means that in the very remote regions of the skin, cells get oxygen but heat isn't lost through this skin.
The feet pose particular problems since they cannot be covered with insulation in the form of feathers or blubber, yet have a big surface area.
In the winter, penguins' feet are held a degree or two above freezing, this minimises taking heat away from the rest of the body, whilst avoiding frostbite.!
2007-04-26 10:58:41 · answer #1 · answered by Anonymous · 0⤊ 0⤋
The muscles that operate feet and flippers are not located in the feet and flippers, but deeper in the warmer regions of the penguins body. The feet and flippers are moved by tendons that pass through them and attach to toes etc. like a sort of remote operation by wire or string. This means that it doesn't matter if the feet and flippers get really cold as they can still be operated normally by regions that are fully functional and at normal body temperature.
Penguins have a heat-exchange blood-flow to these regions. The warm blood entering the feet or flippers flows past cold blood leaving so warming it up in the process and cooling the blood entering at the same time. Blood in these parts is significantly colder than in the rest of the body. By the time the blood re-enters the rest of the body it has been warmed up and so doesn't have so great an effect on the core body temperature.
2007-04-26 05:27:08 · answer #2 · answered by savannah 1 · 5⤊ 0⤋
Who says they don't freeze? I met a penguin at Edinburgh Zoo a few years back and he said his feet were freezing and if wasn't for the regular meals of fish and the nice walks around the place he would have found somewhere warmer to live!
2007-04-26 05:30:26 · answer #3 · answered by Anonymous · 2⤊ 1⤋
I like Savannah's answer but I am sure they can also huddle down where their feet are in the feathers like other birds. Also there is a pouch like layer of fat which they use to keep the eggs warm so I would imagine It would keep their feet warm too.
2007-04-26 10:07:44 · answer #4 · answered by Renee 4 · 0⤊ 0⤋
because the blood to their feet is like anti-freeze
2007-04-27 03:56:58 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Peguins feet dont freeze because penguins are made up of fat. This layour of fat is what makes up their outa body between the bones and the skin. Its what keeps them warm. Just like we would wear a fur coat.
2007-04-26 05:22:06 · answer #6 · answered by John 2 · 2⤊ 3⤋
Because they keep on the move. Even during the four months the males are sheltering the egg, they huddle together and move in a circle, inward--rotating constantly.
2007-04-26 05:25:22 · answer #7 · answered by beez 7 · 4⤊ 1⤋
Because, very obviously, they are designed not to. It would be a bit cruddy of evolution to invent something that lives in the antarctic but cannot survive the cold!!
http://en.wikipedia.org/wiki/Penguins
Chalice
2007-04-26 05:24:02 · answer #8 · answered by Chalice 7 · 1⤊ 1⤋
Just like penguins wonder why we don't melt....
2007-04-26 09:24:24 · answer #9 · answered by Princess 3 · 2⤊ 0⤋
Because they're adapted to their habitat.
2007-04-26 05:24:42 · answer #10 · answered by Anonymous · 3⤊ 0⤋