Z is for Zzzzzzzzzzzz.
The sound of sleep.
We cats, who were originally hunting carnivores, like our sleep. We have to exert lots of energy to catch our prey -- mice, small birds, other small rodents, lizards, frogs, medium sized birds, and maybe even moles. So the rest of the time, we have to conserve our energy. And the easiest way to conserve energy is to sleep.
Even humans like to have lazy Sundays. So if they take a Sunday nap, we can, too.
Sometimes, we sleep on our human's bed. Sometimes, we like to sleep in high places. Sometimes we like to sleep on boxes or in boxes. Other times, we sleep on our humans' laps, or hiding under something. Sometimes we like to sleep with other kitties, if there are other kitties who live with us. Sometimes we want to sleep alone.
When it's time for bed, sometimes we have to prepare our sleeping area by matting down the place where we'll sleep. The humans think it looks like making biscuits.