Why Cats Groom
Domestic cats are meticulous about cleaning themselves. Cats will groom themselves several times throughout the day, with most of their grooming focused on their head. Sometimes it can seem like cats do nothing more than sleep or groom themselves.
Cats clean themselves either by licking the area with their tongue, or by licking their paw and wiping it over a certain area such as their ear. A cat's tongue has a rough texture that removes dirt and loose hair. While they groom themselves cats also coat their hair with their saliva.
As a cat may spend 30-50 percent of its waking hours grooming itself, owners often wonder why cats are so concerned with being clean. But being clean may not be the main reason why cats spend so much time grooming themselves.
Cats are predators, they do not want the scent of their last meal to give them away, nor does the cat want the odor of blood to attract other predators. As such cats groom themselves to remove any scent of blood, meat, and so forth. Even though domestic pet cats may not have these issues or worries, their cleaning instincts are still strong.
In some cases the cat grooms itself to spread its own scent oils throughout its coat. Cats feel more comfortable when they smell their own scent.
To Calm Themselves
Cats who are stressed will often groom themselves to calm themselves. The act of grooming may remind them of when they were young and their mother groomed them. As such grooming can be a bit of self-help to a stressed feline. In some cases stressed cats become obsessive about grooming themselves and may even cause hair loss by doing so.
Not only does grooming cool a hot cat, but it can also warm up a cold one. When water (or saliva) evaporates it creates a cooling sensation, and as such its grooming can account for some cooling of a cat on a hot day. On a colder day the grooming behavior can stimulate blood circulation and thus warm up a chilly cat.
To Remove Loose Hairs
Cat's shed and the loose hairs often get stuck in the coat. This can make the cat feel a little uncomfortable, or even itchy. Their rough tongue removes many of these loose hairs so the cat is not irritated by them.
If a cat has a sore it may groom the area more because its saliva has a slight antibiotic property. If the cat has fleas or mites it might groom itself as a way to try to itch a certain area. If a cat is licking its anal area a lot it may have worms or anal gland problems.
Cats who suffer from thyroid conditions have been observed to engage in overgrooming to the point of causing baldness in some areas. Cats with food allergies may groom themselves as an attempt to itch skin that may be irritated because of the food.