Here’s my segue from Winter Water . . . to the semi-graceful form of winter ducks. The snow is gone, but I still froze my fingers into Rocket Pops, snapping pics of these ducks navigating their own version of tundra.
Unlike me, the ducks kept their digits warm, thanks to the ingenious countercurrent circulation system employed in their feet. In short, the capillaries of a duck’s feet work with the arteries to modulate foot temperature against icy waters, and keep core body temperature warm.
“Arterial blood leaves the bird’s core (trunk) at body temperature, while venous blood in the bird’s foot is quite cool. As the cool blood returns toward the core, heat moves by conductance from the warm arteries into the cool veins. Thus, arterial blood reaching the feet is already cool and venous blood reaching the core has already been warmed.”
~ Ask a Scientist