Cat owners know the scene well. They enter their bathroom to wash their hands, only to find a giant ball of fur engulfing the sink. Their cat has commandeered the fixture, treating the porcelain like a concave mattress. Why do cats do this?

The short answer is similar to what else science knows about cats: Not a whole lot. But there are theories. Speaking with Reader’s Digest, Dr. Rebecca Greenstein, a vet expert with Rover.com, said that cats are attracted to sinks because they offer a pleasing curvature, making them feel nestled and safe. This “denning” resembles how they sleep as part of a litter, with pressure against their bodies.

There are other benefits, too. If a cat has been in a warmer area of a house, like a windowsill, a cool sink surface might be just what they need. Sinks are also typically in a quiet part of the home, giving the cat some much-needed relief from the stresses of their day. Because sinks are raised, cats may also enjoy the feeling of dominance and security that comes with surveilling from a higher vantage point.

There’s no harm to cats filling your sink with their listless, shiftless bodies, but if it’s bothersome, you can always try keeping the bathroom door shut. Otherwise, you’re likely to continue being greeted by a rather large hair clog every morning.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.