Sleeping Cat

When you think of a cat, the picture of a lazy but graceful feline, supine on the sofa or by the fireplace, purring in peace emerges. not surprisingly - cats sleep twice as much as most other mammals. In fact, they sleep away two-thirds of their life.

But a sleepy cat does not necessarily mean a healthy one. And it is important for you to observe your cat's sleeping patterns to detect any unusual change that might be indicative of a silent ailment.

Factors deciding your cat's sleeping patterns include age, hunger, sense of security, weather, temperature, and sexual influences. Be prompt to contact your vet if your cat sleeps for longer than usual, if it looks depressed and shuns company when awake or when you are used to seeing it attentive and playful. Also, if your cat shows weight fluctuations or other physical signs of illness, know that it is time for him to visit the vet.

Most people often ignore a cat that keeps odd sleeping hours by shrugging their shoulders and saying, "well, Garfield is a lazy baby!"

But this could prove dangerous. Any deviation from the normal sleep cycle of your cat, which includes erratic sleeping hours or sleeping for shorter hours, requires immediate attention. The most common cause of this is believed to be hyperthyroidism - when the thyroid gland produces too much hormone and the cat's metabolism shoots into high gear.

Recent studies have also pointed out that cats have dream patterns while sleeping. If you see your feline friend's whiskers twitching and his eyes moving to and fro below his eyelids, Garfield may well be dreaming.

Let him dream, but be careful if he dreams too much!

Cat sleeping patterns

The expression cat nap refers to the light sleeping pattern of most cats, most of the time. About three quarters of a cat's sleeping time is light sleep. The cat can awaken very quickly, and to an observer it looks like they are not fully asleep. Their eyelids may even be slightly open. Again this is genetically related and governed by evolution. A cat that can awaken quickly can more easily escape from predators or fight with possible intruders. The remaining 25 per cent of a cat's sleeping pattern is deep sleep. This is where they do their dreaming. Their paws and faces may twitch during this type of sleep.

Why do they need all that sleep?

Most wild cats use huge amounts of energy when they hunt and they need to conserve energy in between their hunting activity. When a cat (or any living thing for that matter) sleeps, it uses very little energy. The longer a cat sleeps, the more energy it conserves and the less often it has to hunt. Although today's domestic cats don't really need to hunt, their genes are still the same as before we took them into our homes as pets.

Kittens tend to sleep just as much or more than grown cats. This is primarily due to the fact that growth hormone is only released during sleep.

The actual diet of a cat is also a factor. Cats are carnivores. Eating meat makes you sleepy and anyone who's just had a huge steak can attest to this.

• It should be noted that any drastic change in a cat's behaviour can indicate an illness or problem. If your cat normally sleeps only 14 hours for example, and recently it has been sleeping much more, the cat should be checked by a vet.

You can roughly divide sleeping into light sleep and REM sleep. To explain these stages I very much like the sleeping cat examples originally used by the sleep researcher Pouvet. Most of us have seen cats sleep and the two sleep stages can be easily observed in them.

The first stage is light sleep. You can see how the body relaxes somewhat and respiration slows down. This is what you would expect of sleep. It is still rather easy to wake someone up in this stage.

The second stage is REM sleep. The body completely looses all tonus but respiration increases, the famous bursts of rapid-eye-movements show up and occasionally you can see strong almost spastics movements of the limbs. Research on brain activity shows that contrary to the stage of light sleep, the brain is as active as in the waking state. In all, there's a puzzling contradiction between the retension of muscular tension and all the activity that nonetheless is going on. This is why REM sleep has also been called paradoxical sleep. Waking someone up from REM sleep is much harder than from light sleep.

Each following cycle of light and REM sleep tends to shift more focus to the REM stage. With humans, the first cycle has a relatively small REM component that only shows up after more than an hour of light sleep. However, at the end of a six to eight hour sleeping period most time tends to be spent in REM sleep.