|
 |
|
|
|
Meet George - a penguin. |
|
|
|
|
|
George and his friends here are brilliantly designed birds. They're just as happy in freezing water as on land. But how do they keep their little bodies warm in such freezing cold temperatures? |
|
|
|
|
|
Well, they have a fatty layer of blubber all over their bodies which helps to keep them warm. A bit like wearing a big coat! |
|
|
|
|
|
However - further down the penguin's body, there appears to be a design fault. Their feet are completely bare - no blubber or feathers at all. |
|
|
|
|
|
The bare legs are no problem because the fatty blubber just hangs over the top of them, so keeping them warm. |
|
|
|
|
|
So how do penguins prevent their feet from freezing? Well, it's down to a very clever design system. |
|
|
|
|
|
This is a model of a penguin's leg. The warm blood from the penguin's body travels down into the feet and back up the other side of the leg. The circulation of the warm blood prevents the leg from freezing. |
|
|
|
|
|
The system is so effective that not only can it send blood down into the feet, it can send it across the legs, so that most of the warmth stays near the body, and just enough is allowed to reach the feet, to stop them freezing. |
|
|
|
|
|
Brilliant! So George's feet are kept at a constant temperature of one or two degrees above freezing, so he doesn't get frostbite or lose any body heat. |
|
|
|
|
|
The system is so great that the centre of the penguin's body stays at a constant 40 degrees celsius, which is even hotter than ours (at just 37 degrees celsius). |
|
|
|
|