MINNEAPOLIS (WCCO) – This week’s extreme cold left a fifth grade class with a Good Question about our feathered friends.

We had some cold nights this week, but the birds didn’t all just fly south for the winter. Tim Simonson’s 5th graders wondered: How do ducks survive swimming in near-freezing water?

Ducks and all cold-weather birds have a pretty brilliantly-designed circulation system to help them deal with cold water. It’s called countercurrent.

Their veins and arteries run really close together. The veins rush cold blood towards the heart. The arteries rush warm blood towards the feet.

Because the veins and arteries are close, they both stay fairly cool, but warm enough to protect the tissues. Humans have a similar, but less-developed system, because we don’t need it that often.

Dana from Spicer, Minn., asks a question I’ve long wondered about: Why are horoscopes printed in the newspaper?

The first newspaper horoscope column was written in 1930 just after the birth of Princess Margaret. The assistant to the famous astrologer Cheiro was asked by the Sunday Express newspaper to make a few predictions based on the Princess’s birth chart.

Alongside it, he wrote predictions for those born on each day of that month. The public response was enthusiastic and soon the horoscope column was born.

Bruce from Minneapolis wants to know: Why is the Super Bowl referred to as the “Big Game?”

The NFL owns the copyright to the term “Super Bowl.” We can say it in the news, but we can’t use it in marketing materials.

We can, however, say “The Big Game in New Orleans,” “the Professional Football Championship Game in New Orleans,” “the February 3rd Game,” and “San Francisco vs. New England” — but we can’t say the team names.

You can also make fun of the fact that you can’t say the phrase “Super Bowl,” by bleeping it out.

You can catch that “Big Game,” or whatever you’d like to call it, on WCCO on Feb. 3.