Why do cats sleep so much?

Because they are evolved as crepuscular ambush predators, and everything about their energy budget follows from that.

The typical figure is 12 to 16 hours a day, with kittens and older cats sleeping more — sometimes 20 hours.

The evolutionary logic. Hunting by ambush is extraordinarily expensive in short bursts: explosive acceleration, a chase, a kill. A wild cat's diet of small prey provides limited energy per catch, and many attempts fail. Conserving energy between hunting opportunities is therefore the optimal strategy. Sleeping is not laziness; it is how the energy budget balances.

Crepuscular timing means cats are naturally most active around dawn and dusk, when their prey is active and light levels suit their vision. This is why a cat that slept all day becomes energetic at 5am — it is following an ancestral schedule, not being deliberately inconvenient.

Much of it is not deep sleep. Cats spend a large proportion in light dozing — the familiar posture with ears still swivelling toward sounds. They can rouse instantly. Genuine deep sleep, including REM, occupies a much smaller share, and this is when you see twitching paws and whiskers.

What influences it:

Age. Kittens sleep enormously because growth hormone is released during sleep; senior cats sleep more as activity declines.

Weather. Cats sleep more in cold or wet conditions.

Boredom. An indoor cat with nothing to do sleeps more than one with stimulation — which is an argument for play sessions rather than a fact to accept.

Food security. Reliable meals remove the need to hunt.

When to be concerned. A sudden change is more meaningful than the absolute amount. Markedly increased sleeping alongside reduced appetite, hiding, reluctance to jump, or changes in litter tray habits warrants a vet visit.