When Do Kittens Stop Growing?

Are you the proud owner of a new kitten? Are you wondering how big your kitten is going to get? And, how long does it take for a kitten to grow into a full-size cat?

Just like human babies, kittens go through a number of different growth stages. Exactly when a kitten stops growing and becomes an adult cat depends on a number of factors such as the breed, whether they have had any significant health issues, and whether they have been neutered.

In this article we’ll cover the following;

• How Quickly do Kittens Grow?
• How do Kittens Grow?
• When do Kittens Reach Full Size?
• Why do Kittens Grow so Fast?

How Quickly do Kittens Grow?

Kittens don’t grow at one consistent speed on their way to becoming an adult cat. In fact, their growth can be divided up into a number of different growth stages.

To get a better idea of how quickly one particular kitten grew up, let’s look at a video that shows them from 12 weeks to a year old:

Quite a change, right? If you were to weigh this kitten, you would obviously find that they were getting heavier and heavier in each scene. But some weeks they would appear to be growing faster than others.

This is because kittens go through “growth spurts.” While kittens do grow constantly from when they’re born until they are an adult cat, there are certain times in their early life where they seem to be growing really fast.

During their first week, newborn kittens grow super-fast and will double their weight. Their next growth spurt comes when the kitten begins to transition into eating solid food, at around four to six weeks old. The last “growth spurt” usually occurs when your kitten is between four and six months of age.

After month six, your kitten will keep growing, but it will be at a slower and slower rate. Keep in mind, these particular growth spurts can vary, depending on a number of factors, such as the breed of your cat, the nutrition they are getting, and whether they have any health problems.

The main thing to remember is that your kitten should be noticeably growing and gaining weight until they’re well past 8 months of age. They definitely shouldn’t be losing weight. If your kitten loses weight, or isn’t a ball of energy (except when they’re crashed out asleep), it’s a good idea to take them to the vet for a checkup. Another time to visit your vet is if your kitten is shaking.

How do Kittens Grow?

The simple answer to this question is that kittens take the fat, protein, and carbohydrates they consume from mama cat’s milk and the cat food you give them and use them as the building blocks for their own bodies. To understand how a cat’s growth process works over time, veterinarians and scientists talk about “growth stages.”

Growth stages are subjective, in that different scientists or veterinarians often break them up into different groups of weeks. The important thing is that the concept of growth stages allow you to track your kitten’s various milestones as they grow up. That way, we can understand the changing needs of your kitten as they become an adult.

Below is one breakdown of kitten growth stages from one week to one year:

Stage I (newborn, the first week)

• ears open, but still deaf
• eyes begin to open
• kitten’s umbilical cord stub will fall off
• huddle with mom for warmth
• gain twice their birth weight

Stage II (toddler, weeks two through four):

• eyes fully open
• ear canals open
• sense of smell develops
• kittens start moving, exploring and playing with each other

Stage III (weeks five through nine)

• kitten transitions from mama cat’s milk to solid food
• kitten starts using the litter box
• beginning of socialization

Stage IV (weeks ten through 23)

• kittens are fully weaned
• lose baby teeth and start growing adult teeth

Stage V (adolescent, 24 to 52 weeks old)

• growth rate slows
• kittens become sexually mature
• adult weight and length usually achieved

When do Kittens Reach Full Size?

It takes about 1 year for a kitten to grow into a full size cat. This can vary considerable depending on the breed of cat you are talking about. Generally, the larger breeds of cats take quite a bit longer to attain full size.

For example, the Maine Coon is generally considered to be the largest breed of domestic cat. Males can weigh up to 18 pounds (8.2 kg) and females weigh up to 12 pounds (5.4 kg).Including their tail, Maine Coons can reach a total length of up to 48 in (120 cm).

Maine Coons often don’t reach their full potential size is until they are between three to five years old.

The scientific way to tell when a cat is fully an adult is when their bones stop growing. This is called epiphyseal plate closure or sometimes just physeal closure.

Basically, the long bones of mammals actually grow from the ends of the bone outward. Bone cells division occurs along a plate between the end of the bone and the cartilage attached to the bone. When the cells in this plate stop dividing, the bones stop getting longer and the plate is said to have “closed.”

One thing that can influence when physeal closure occurs is neutering your cat. Physeal closure seems to occur later in neutered male cats, so this means that they might grow for a little bit longer than intact cats will.

Why do Kittens Grow so Fast?

Kittens do seem to grow up really fast. But, is this actually the case? How fast do cats grow compared to other mammals?

Well, blue whales grow more than 30 pounds a day and doubles in size by 6 months of age. Shrews grow up, have 4 to 12 litters of baby shrews, grow old and die all in less than three years.

One thing scientists have found is that how fast an animal grows depends a lot on how much energy is spent by the animal growing their brain. Humans, spend a lot on growing their big brains, so we grow up really slowly. Cats, with their smaller brain can put more energy towards their body growth, so they physically mature much faster.

Watching your Kitten Grow

Watching your kitten grow up is one of the best parts of having a cat for a pet. A great way to keep track of your kitten’s milestones is to get a good book that can tell you all you need to know about your kitten’s development milestones. Also, make sure you take your kitten to the vet so he or she can reach their full potential as the grow into an adult cat.

If you have any questions or would like to share a story about your kitten and how fast they are growing, please tell us in the comments below, we’d love to hear from you.