Silly thoughts - ducks

Yeah... so when we were driving to church yesterday, I noticed a bunch of ducks swimming in a pond on the side of the road. I started to wonder if they needed to keep paddling their feet to stay afloat and whether or not they can sleep on the water. Now, I know that they can because I've seen them (I think), but somehow I started to wonder if that's true because humans can't float and sleep at the same time (right?). So I turned and asked Dan. He said no, the ducks don't need to paddle to float and that they can sleep on the water. I said, oh, okay...