Tiny kittens are the bee's knees, that's for sure. With the passing of a little time, however, they all inevitably grow into something arguably even more adorable -- adult cats. Cats often reach maturity in what seems to humans like the blink of an eye -- just a couple of years.
Domestic house cats exist in roughly 30 distinct breeds, so they run the gamut in terms of size. Singapura cats are particularly small, while Maine coons, on the other hand, are particularly big. Domestic shorthair and long-haired cats are usually somewhere in between. Male cats, however, generally weigh a little more than the females. At maturity, cats typically weigh between 5 and 20 pounds. Their mature bodies usually grow to around 28 inches in length, as well. Note that cats and dogs who were neutered or spayed at early ages often don't grow as big as their intact buddies.
Fully Grown Adults
Cats attain full grown status when they're between 2 and 4 years old. This generally depends on the specific breed. Sizable Maine coons, for instance, often don't complete the growth process until they're around 4 to 5 years in age, later than in many of the other feline breeds. Feline bones generally cease growing when they're approximately 1 year old. Most of their growth and bodily development after that consists of taking on a slightly thicker and more dense appearance.
Age of Sexual Maturity
The age of sexual maturity doesn't translate to full grown in the feline universe. Cats typically gain reproductive capabilities well before their furry bodies stop growing. This usually occurs when they're between 6 and 9 months old, although exceptions often occur. Cats of certain breeds are often early bloomers -- think Siamese cats. When cats reach sexual maturity, they usually are only about 80 percent of the way to their eventual adult weight.
Feline development is a relatively swift process. When kittens are a mere 6 months, they are similar developmentally to 15-year-old adolescent humans. When they're 7-year-old adults, they're a lot like 50-year-old humans. By the time they get to a ripe and wise 20 years in age, they're pretty similar to human centenarians. The speediest growth, however, takes place in their youth.