Cats sleep 15-16 hours a day on an average, but some cats may sleep up to twenty hours a day. Which raises the question: why do cats sleep so much?

Reasons for excessive Cat sleeping

All that sleeping is in Cat’s genetics
That more sleeping habit is developed in them due to Cat’s evolution and genetic factors. Because in the past, Cat wild ancestors have to hunt for food via chasing and killing prey which burns a lot of energy. So excessive sleeping helps cats save life between meals.
Snoozing is also considered sleeping in cats
About three-quarters of the time a cat sleeps is what we call snoozing. In this case, the cats can get all the rest they need, but they are still alert enough to wake up at a moment’s notice. You can differentiate snoozing from deep sleep very quickly. When a cat is in snoozing state its ears rotate and turn towards noise and its eyes open a little bit while deep sleep is opposite
Cats sleep deeply and even dream
Cats spend the remaining one-quarter of their daily routine in a deep sleep, but older cats spend up to 35-40% of their daily time in a deep sleep. Cats in a deep sleep usually curled up with their eyes closed tightly. Sometimes, they even put their tails on their face, like a sleeping mask. Deep sleep is essential for the body’s ability to stay fit and healthy and regenerate. This is also the time when your cat dreams. If your Cat is twitching its whiskers and paws while sleeping, there’s a good chance she is dreaming.
Some cats snore while sleeping
Cats snore when the airway is blocked by extra skin from the soft palate. This is most likely when your Cat is relaxed, so it won’t be annoying for your Cat to saw some tiny little logs from time to time. Snoring is more likely to occur in brachycephalic, short-nosed or tilt nose cat breeds such as Himalayan, Persian, American Shorthair or Exotic Shorthair.
Tip: Sleeping is also affected by nutrition habits and physiology of particular cats.
A change in your Cat’s regular sleeping routine can be a sign of anxiety
When you ask, “Why do cats sleep so much?” You may also wonder if there is such a thing as too much – or too little – sleep. If your cat sleeps more or less than usual, contact your veterinarian. Excessive sleep can be a sign of pain or illness, while frequent awaking can indicate a problem such as hyperthyroidism.
Why does the Cat sleep in different places from time to time?
Changing sleep patterns and locations is a cat’s instinct, and reminds us that cats can be domesticated, but they’re just a little away from being wild.
In the wild, cats developed the habit of changing their sleeping areas to protect themselves. Cats’ sleeping spots soon pick up their scent, allowing predators to recognize them. So they move around a lot in their territory. Today’s domestic Cat has retained this characteristic, although most homes do not have predators that hunt cats.
Cats will also change their sleeping place depending on the temperature. When it’s cold, they prefer a warm, comfortable home. On hot days, they can choose the bathroom sink as their primary location or favourite napping spot. This may not sound like your Cat’s case, but the discomfort can be caused by frequent or permanent switching to different sleeping areas.