Kittens are curious and crave constant stimulation. A single, bored kitten will often entertain itself by chewing on plants, climbing drapes, climbing furniture, unrolling toilet paper, exploring electrical cords and sockets, etc. This is not to say that kittens who live with other kittens won’t also sometimes do these things, but if they have another kitten to tumble around and play with, it is less likely that they will need to entertain themselves with behaviors like these, which at the least are destructive and at the worst can be very dangerous.
Kittens tend to be very active at night. A single kitten is likely to keep the owner awake with constant jumping, pouncing and other hunting behavior directed at any portion of the owner’s body which moves under the bed linens. With a companion to play with after the owner has gone to bed, this behavior is minimized as the two will occupy each other by finding interesting shadows to chase and games to play until they finally tire and fall asleep too.
Kittens want and need interaction with others of their own kind for healthy social development. A kitten learns a lot in the first several months of life from its mother and littermates. Separating a kitten from its mother is often a necessity in order for it to be adopted, but taking it away from its littermates and isolating it can delay the kitten’s development emotionally, socially and sometimes physically. Kittens that are able to remain with one of their littermates or a similarly-aged companion, tend to be healthier and happier, and in the long run, better socialized pets than those who are isolated from others of their kind at an early age.
Anyone who has observed kittens knows they want to bite and wrestle with one another–this behavior is normal. You cannot prevent a kitten from doing what comes naturally anymore than you can force a two year old toddler to sit still. Though it is not acceptable for a kitten to bite and wrestle with its human companions, in the absence of having a littermate or companion its own age to play with, this is precisely what a single kitten will want to do. Even if you are willing to allow (and can tolerate) this behavior from your kitten when it is small, by the time the animal matures, you will end up with an adult cat who has developed very bad habits (for example, biting and scratching as “play”).
Humans, even loving, caring humans, are not an adequate substitute for a cat in lieu of one of its own kind. Even if the owner is fortunate enough to be home quite a bit, the amount of attention a lone kitten will demand is likely to occupy all of the owner’s waking hours at home. A pair of kittens will definitely still want to interact with the owner, but can keep each other occupied while the owner is doing such necessary tasks as working, paying bills, having telephone conversations, gardening, laundry, etc. Most cats, regardless of their age, are highly sociable and are truly happier living with other cat companions. This in turn makes them better pets, which results in happier owners.
Particularly if there is already an older cat in the household, a kitten should not be brought in as a lone companion. As mentioned above, a youngster has boundless energy, wants to play and run constantly, and requires very high amounts of interaction, all of which are likely to overwhelm and irritate an older cat in short order. Likewise, a kitten is apt to be frustrated that its companion does not have the same energy level as itself. At the very least, this can lead to two very unhappy cats. Worse-case scenario, behavior problems such as litter box avoidance or destructive scratching can occur if one or both cats act out their frustrations on their surroundings. Longer-term, it is almost certain that the two will never have a close, bonded relationship, even after the kitten matures, since their experiences with one another from the beginning of the relationship are likely to be negative. An older cat is better matched with someone of his or her own age, who has a similar temperament.
Adopting a single kitten or young cat is simply not a good idea. Trying to keep a single kitten occupied, stimulated, safe and happy while also going about the business of everyday life is much more of a challenge than it may seem upon first consideration.
We understand and accept that someone out there will probably adopt or sell you a single kitten. With that in mind, please think long and hard about forcing a kitten to become an only child. Mother Nature knew what she was doing when she created kittens in litters!