Why don't a penguin's feet freeze?
May 20, 2010The 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.
Posted by Dr Roberts. Posted In : Why don't a penguin's feet freeze? And other Q's