Do birds get cold feet?
Short answer is no! The longer answer is no because (physics coming up , sorry), if you put something warm next to something cold the warmer molecules will give up their energy, in the form of heat, to the cold thing. As has been said you can’t change the laws of physics! Heat energy is shared until things are at the same temperature – the laws of physics. The problem faced by ducks, geese, waders, etc. is the blood flow through their feet.
The blood heading from their hearts is around 40°C and some of it is travelling to their feet which can be in freezing water. So, the warm blood would give up its heat very rapidly to the cold water. If that, now chilled blood, got back to the rest of the duck it would take heat away from the warm blood causing the rest of the duck to cool down – not good for the duck. It would need to produce more heat by burning stored food reserves (fat), and would then need to forage for more food.
What’s to be done?
Well ducks, etc. have evolved a simple, but brilliantly ingenious, solution. The arteries (warm blood) and veins (cold blood) in their legs are very close together. This means the warm blood heats up the cold blood heading back to the heart via the veins and this process is happening all the way down the duck’s legs. So, by the time the once warm blood reaches the duck’s feet it is more or less at the same temperature as the colder blood so it has little heat to lose. The colder blood heading back to the duck’s heart has been gaining heat all the way so is more or less at the temperature of the rest of the duck, therefore it has very little heat to gain, simples!
A brilliant adaptation to answer the question Do birds get cold feet?
Makes you wish you had paid attention in school really.
David Haines