On any given night, or actually about 91% of the time, give or take a few decimal points, if anyone asked to see my dogs sleeping habits, I would instruct them to go to their nearest blanket, shove a pillow under it, and gaze lovingly at their vet bills hard at work.
Cats don't sleep under covers. I would think because they know they are lethal at any given moment, they never fully let their guard down enough to be attacked, they... They could very well sleep under covers for all I know. The only thing I can be sure of is that if a cat were under my covers, I would probably see my dogs more often.
This still made my inpenetrable heart of steel warm a touch today.