Why Do Cats Sleep So Much?

On average, adult cats sleep between 12 and 16 hours per day. Senior cats and kittens sleep even more, spending around 80% of their lives in slumber. Why do they sleep so much? Different theories suggest that this habit may be related to ecological factors such as predation risk, the need to conserve energy in the wild, and cats' solitary nature. Sleep is also essential to memory formation, and in kittens, long periods of sleep and intense brain development go hand in hand.

Typical Cat Sleep Habits

Cats reach adult sleep patterns at around 7-8 weeks of age, at which point they spend 50% to 70% of a 24-hour period asleep. Their daily peak activity in the wild can vary depending on when prey is available nearby, meaning that they're often ready to eat or play at inconvenient times. Most cat owners recognize this quality when their cat wakes them up at 5 a.m., often begging for food or to be let outside.

The cycle of waking and sleeping for cats is relatively variable, with several short periods of sleep during both day and night, rather than one long, uninterrupted slumber. A particular part of the brainstem called the reticular formation is considered a major control center for sleep in cats, sending nerve impulses to the cortex to keep the cat awake. These nerve impulses are also impacted by sensory observations, like the visual characteristics of a potential threat. Hunger and thirst have also been shown to suppress sleep in cats.

When cats are awake, rhythmic activity in the brain can vary greatly depending on the level of activity the animal is engaged in. When a cat falls asleep, rhythmic patterns in the brain reach a lower frequency, and the cat typically enters a period of 10-30 minutes in which it appears to be sleeping, but will wake up immediately if roused. The cat then enters a period when its brain patterns are at a higher frequency, similar to wakefulness, but do not easily wake up. This period, known as paradoxical sleep, is considered the REM stage for cats, and their muscles normally almost completely lose tone. After about 10 more minutes, the cat returns to lower-frequency rhythmic patterns during sleep, and may alternate in and out of these stages several times during a long nap.

During the paradoxical sleep phase cats may twitch their tails, blink their eyes, and move their whiskers, leading some owners and scientists to theorize that cats do dream during this stage. There is no direct evidence for that, but we do know that paradoxical sleep is more important than normal sleep, so it's best to avoid waking up your cat when it's deeply asleep. Kittens especially need ample deep sleep for their development. To keep your cat sleeping comfortably, provide it with a clean, warm, soft space, as cats relax and may be more likely to enter restorative sleep when warm. When cats are lightly sleeping, they'll commonly wake up to any number of sounds, similar to how they would react to nearby sounds in the wild.

Waking Hours

In the wild, cats are opportunistic predators that can coordinate their hunts to the time of peak activity of the easiest available prey. As a result, cats can also change their schedules to accommodate their owners, sometimes sleeping all day if the house is empty, or sleeping most of the night along with human members of the household. That said, because cats' sleeping patterns differ and each sleep is shorter in duration than a human's would be, they're still likely to wake up and have active periods while owners are away or sleeping.

Cats' daily activity changes seasonally. For example, their food intake peaks in autumn and is lowest in the spring, and their body weight is highest in summer and lowest in mid-winter. In the wild, cats are generally awake for a couple of hours at a time, often returning to successful hunting spots and looking for more food. The amount of time cats spend hunting varies depending on many factors, including whether or not a female cat has kittens waiting on her return, leading Cambridge researchers to theorize that cats aren't only hunting for food and sometimes spend additional time tracking prey for other reasons, including entertainment.

For domestic cats, it's important that owners replicate the cat's natural outdoor activity, providing them with interactive toys and playtime every day for half an hour or so, at least once, and more often for especially active cats. This is particularly true for cats without access to the outdoors. Domesticated cats will often hunt for prey and play outside, even shortly after a full meal.

How Much Sleep Is Too Much? 

It's normal for cats to sleep a lot, particularly when they're very old or very young. The key to identifying medical conditions that may require special attention is noticing the changes in their sleeping schedules.

Many senior and geriatric cats experience a decline in cognitive function as they age and may show signs of sleep restlessness as a result. Cats with feline immunodeficiency virus (FIV) spend more time awake and often have shorter periods of sleep than healthy cats. Changes in schedule and duration of your cat's sleep could be an indication of illness and could require a trip to the vet.