The young of species in the genus Panthera and of some other big cats are called cubs rather than kittens. Either term may be used for the young of smaller wild felids such as ocelots, caracals, and lynx, but "kitten" is usually more common for these species.

Though the term primarily refers to young cats, it can also be used when talking about the young of rats, rabbits, hedgehogs, beavers, squirrels and skunks.

Birth and development

For the first several weeks, kittens are unable to urinate or defecate without being stimulated by their mother. They are also unable to regulate their body temperature for the first three weeks, so kittens born in temperatures less than 27 °C (80 °F) can die from exposure if they are not kept warm by their mother.

The mother's milk is very important for the kittens' nutrition and proper growth; so if possible, the kitten should not be taken from their mother for at least 8 weeks after birth. This milk transfers antibodies to the kittens, which helps protect them against infectious disease. Newborn kittens are also unable to produce concentrated urine, so have a very high requirement for fluids.

Kittens open their eyes about seven to ten days following birth. At first, the retina is poorly-developed and vision is poor. Kittens are not able to see as well as adult cats until about ten weeks after birth.

Kittens develop very quickly from about two weeks of age until their seventh week. Their coordination and strength improve, they play-fight with their litter-mates, and begin to explore the world outside the nest. They learn to wash themselves and others as well as play hunting and stalking games, showing their inborn ability as predators. These innate skills are developed by the kittens' mother or other adult cats bringing live prey to the nest. Later, the adult cats also demonstrate hunting techniques for the kittens to emulate.

As they reach three to four weeks old, the kittens are gradually weaned and begin to eat solid food, with weaning usually complete by six to eight weeks. Kittens live primarily on solid food after weaning, but usually continue to suckle from time to time until separated from their mothers. Some mother cats will scatter their kittens as early as three months of age, while others continue to look after them until they approach sexual maturity.

Kittens are highly social animals and spend most of their waking hours interacting with available animals and playing. Play with other kittens peaks in the third or fourth month after birth, with more solitary hunting and stalking play peaking later, at about five months. page 18 Kittens are vulnerable to harm because they like to find dark places to hide; with sometimes fatal results if they are not watched carefully.