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When Does a Maine Coon Kitten Become an Adult Cat?

A tabby Maine Coon kitten with blue eyes sitting on a gray fuzzy rug.

Taking care of a cat can be incredibly fun, but it can be a bit anxiety-inducing to raise one from a kitten if it’s your first time doing so. You might find yourself asking, “When does a kitten become a cat? How will I know?” I’ve personally raised a few kittens over the years that were all precious in their own way, but one of the most memorable was an affectionate Maine Coon kitten that I received as a gift from a friend’s litter. Watching him grow up was a wonderful experience.

A Maine Coon is typically considered a kitten at 0 to 6 months, a junior adult at 6 months to 2 years, an adult at 2 to 6 years (also known as their prime years), a mature adult at 6 to 10 years, a senior at 10 to 14 years, and a super senior or geriatric at 14 years and older.

If you’re interested in learning more about these phases and the traits associated with them or the care you should be giving your Maine Coon during said phases, keep on reading!

Maine Coons: The Largest Domestic Cat Breed

If you’ve raised kittens before, you’re probably familiar with their general size as they grow. That’s why it can be surprising to raise a Maine Coon — because they’re the largest domestic cat breed, they can reach typical “cat” sizes even when they’re still kittens.

FACT: It can take around 4 to 5 years for them to reach their full adult size.

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On average, Maine Coons are around 40 inches in length (including the tail) and 10 to 16 inches in height. They weigh around 9 to 18 pounds, although some larger cats may come in at around 25 to 30 pounds. They have muscular bodies with solid legs and wide chests, and their long, fluffy coat makes them look even bigger.

Maine Coons are known for being “gentle giants,” due to their affectionate nature and large stature. They’ll enjoy following you around the house and lying down beside you, and appreciate a lot of affection and playtime in return.

DID YOU KNOW? Currently, the largest Maine Coon alive is an Italian cat named Barivel, who measures 3 feet and 11 inches in length.

Kitten Phase: 0 to 6 Months

When Maine Coon kittens are born, they don’t look much different from other kittens. At birth, they typically weigh about 3.5 to 5.0 ounces. However, within the first week, they usually double in weight.

During this phase, they’re completely vulnerable — they can’t see or hear, or keep themselves warm and eliminate waste on their own. They’re dependent on their mother (or you) to take care of their needs.

A white and tabby Maine Coon kitten with black ear tips and green eyes.
Maine Coon kittens are dependent on their mothers during their first 6 months

If you’re adopting from a shelter or getting the kitten from someone else, you’ll likely receive them at 10 to 12 weeks old, weighing around 3 to 5 pounds. At this stage, they should be fully weaned and socialized and ready to move into a new home. They’ll be curious and energetic, interested in playing and pouncing around the house and developing their coordination skills and instincts.

During the first few months, a Maine Coon kitten grows hair quickly, which gives the impression that they’re maturing quickly. Don’t be fooled — even under that mass of hair, they’re still kittens.

NOTE: If you want to spay or neuter your kitten, the best time to do it is between 4 to 6 months.

Junior Adult Phase: 6 Months to 2 Years

When does a Maine Coon kitten become a cat? During this phase, you can consider your Maine Coon kitten a young adult or a young teenager, beginning their transition into adulthood. At around 6 months to the end of the first year, you’ll notice your cat continuing to grow fur.

Their coat may reach as long as 4 inches, giving them a fluffier appearance. You can expect rapid growth and weight gain during the first year. They’ll still be a tad rambunctious during this time, but they may also start mellowing out and letting some maturity shine through.

You can keep feeding them kitten food until they’re around 15 months old. Kitten food is packed full of calories, protein, and fat meant for encouraging healthy growth, so it’s good for helping your cat grow bigger and stronger.

By the time they’re 2 years old, you can start feeding them adult cat food. Try this high-quality cat food from Amazon. At this point, they will have grown most of their adult hair.

NOTE: Some Maine Coons will also develop “lion manes” (additional fur around their neck and chest) or “lynx tips” (small tufts of hair on the top of their ears), which are signature Maine Coon characteristics.

Adult Phase: 2 to 6 Years

It takes around 2 to 6 years until a Maine Coon kitten truly becomes an adult cat. One of the tell-tale signs that they’re no longer kittens is a more mature personality — instead of jumping from cabinet to cabinet, they may now prefer lazing around or snuggling up to you on the couch to spend some quality time instead.

NOTE: Of course, even when they are adults, Maine Coons can still be energetic and playful here and there, but they won’t be as unrestrained as in the first few years of their life.

A tabby Maine Coon cat that is not quite full grown.
Maine Coon cats calm down during this phase

During this time, they’ll continue growing in size, weight, height, and maturity, but at a slower pace than before. You can expect your Maine Coon to reach their full adult size at around 4 to 5 years.

Compared to other cat breeds, which reach adulthood at around 1 year old, Maine Coons reach full maturity more slowly, but they make up for it with their impressive stature.

NOTE: On average, female Maine Coons will be smaller than males — females tend to weigh 9 to 16 pounds while males tend to weigh upwards of 13 pounds.

Mature Phase: 6 to 10 Years

As your Maine Coon cat continues to age, it’ll gradually become gentler and wiser, similar to us humans. At this stage, they’re the equivalent of a 44 to a 56-year-old human.

Their muscles may start deteriorating and aches and pains will start cropping up. They’ll likely begin to reduce their physical activity, so it’s good to keep an eye on their diet to ensure they don’t gain too much weight.

You should make it a point to visit the vet at least once a year for routine checkups and bloodwork. This will help you detect potential health issues early on, which often makes them easier to treat and increases your pet’s chances of recovering fully.

Senior Phase: 10 to 14 Years

Now that your Maine Coon is much older, you may notice significant changes in its habits and behavior. They may be more lethargic, choosing not to exert themselves due to aches and pains worsening.

NOTE: If you observe any lumps and bumps, significant changes to their movement, excessive thirst, loss or increase of appetite, or problems toileting or sleeping, it’s best to get it checked.

Geriatric Phase: 14 Years and Older

The average lifespan of a Maine Coon is around 10 to 15 years, so when your cat has reached such an old age, be sure to treasure every moment with them.

Under the best circumstances, your cat may reach well beyond 15 years — the previous world record holder for the oldest living cat was a Maine Coon named Rubble, who lived until he was 31 years old.

Here are some factors that can affect the lifespan of your cat:

  • Indoor cats generally live longer.
  • Feed them a healthy diet. Try to focus on a high protein, low carbohydrate diet to avoid obesity.
  • Ensure that they get enough interaction and exercise, which benefits both their physical and mental health. This will be easy when they’re young and energetic, but you should keep up with the playtime even when they grow older and more lethargic.
  • Don’t stress them out too much.
  • Take them on regular visits to the vet, especially as they grow older, to detect any health problems before they worsen.
A white and tabby Main Coon cat with black tipped ears and green eyes.
Maine Coon cats grow from tiny furballs into loving gentle giants

Wrapping Up

So, when does a Maine Coon kitten become an adult cat? They begin transitioning to adulthood at around 1 to 2 years old, but they don’t reach full maturity until 4 to 5 years old.

Throughout their lives, Maine Coons will be affectionate, playful companions that fit right into a loving home. Don’t be afraid of taking on the responsibility of raising them from a kitten — their growth from a tiny fur ball to a gentle giant is a sight to behold.

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