Question

Gulls, ducks, and geese can stand on ice without freezing their feet because of this adaptation:

Select one:
a. in the fall covering the feet with a thick layer of down and contour feathers
b. pumping more blood into their extremities to raise their internal temperature
c. developing a thick layer of white fat under the skin of the feet for insulation
d. activating a counter-current heat exchanger known as the rete mirable
e. all of the above

Answer 1

Gulls, ducks, and geese use a counter-current heat exchange system called the rete mirable to prevent their feet from freezing on ice.

Step-by-step explanation:

Gulls, ducks, and geese can stand on ice without freezing their feet primarily due to option d.: activating a counter-current heat exchanger known as the rete mirable. This adaptation allows these birds to maintain their body heat while standing on ice. The rete mirable is a complex network of blood vessels that causes warm arterial blood heading towards the feet to pass very close to the cold venous blood returning from the feet to the body's core. This system allows for the transfer of heat from the outgoing blood to the incoming blood, thus conserving body heat and preventing the extremities from freezing.