Is Your 5 Month Old Kitten Still a Baby? The Truth About Cat Development Stages

Is 5-Month-Old Kittens Still Considered Babies?

Kittens go through several distinct stages of development from birth to adulthood. While a 5-month-old kitten may seem fully grown, they still have a lot of maturing to do. In this article, we’ll look at the various phases of development kittens go through and examine if 5 months old is still considered a baby in the cat world.


Kittens go through several growth stages before reaching full maturity and becoming cats. Here are the definitions of the different stages:

A kitten is a baby cat generally under 1 year old. According to Purina, kittens are classified in these age groups:[1]

  • Newborn: 0-2 weeks
  • Infant: 3-8 weeks
  • Junior: 9-12 weeks
  • Prime: 3-6 months

A cat is a feline that has reached adulthood, which occurs around 1 year old. As Untamed Cat Food explains, A kitten is fully grown by the time they turn one year old.[2] At this point, kittens have reached their adult size and weight.

So in summary, a 5 month old feline is still considered a kitten, in the “prime” stage of development before becoming a full grown adult cat around 12 months old.


Growth Stages

Kittens go through rapid physical development in their first year of life. According to the ASPCA, kittens are considered newborns from birth until 2 weeks old. From 2-7 weeks they are in the socialization period. By 3 months old, kittens have their adult teeth and reach 90% of their adult size. From 6-12 months kittens go through adolescence and reach their full adult size and sexual maturity.

According to Hill’s Pet Nutrition, in the first month kittens will double their birth weight. By 3 months they gain about a pound per month. Most domestic cats reach their full adult size between 9-12 months old. Male cats tend to be larger than females. The average domestic cat weighs 8-10 pounds at maturity.

Some key physical developments in a kitten’s first year include:[1]

  • Eyes open around 1-2 weeks
  • Ears open and kittens start walking around 3-4 weeks
  • Baby teeth erupt around 3-4 weeks
  • Weaning starts around 4-6 weeks
  • Adult teeth come in around 3-6 months
  • Reaches 90% adult size by 3-5 months
  • Reaches sexual maturity between 6-10 months

While the average kitten is considered an adult at 1 year old, some larger breed cats like Maine Coons don’t reach full maturity until age 3-5.



Kittens and adult cats exhibit some key differences in behavior. Kittens are famously playful, curious, and energetic. They need multiple play sessions per day to expend their energy and learn proper cat behaviors. Kittens love to play hunt, chase toys, climb, wrestle, and explore their surroundings. This rambunctiousness can be endearing but also exhausting for owners. Kittens may get into mischief and can be destructive with their scratching, biting, and knocking things over if not properly trained and supervised.

According to Meow Cat Rescue, adult cats are generally much calmer than kittens. While adult cats still need playtime, they have less pent up energy and are happy to relax and lounge between play sessions. An adult cat’s personality is already developed so owners have a better sense of what to expect in terms of activity level. Adult cats are less likely to get into trouble with rough play and destruction. Their calmer temperaments can be a better fit for quieter households.

As kittens mature into adult cats, their extreme energy levels diminish. By 1-2 years old, Laveen Vet Center notes most cats have settled into a more moderate activity level characteristic of adulthood. Their play becomes less frenzied but they still enjoy interactive playtime with their owners. With proper training and socialization as kittens, adult cats develop good manners and curb destructive behaviors. While an adult cat is more sedate than a kitten, each cat has their own individual activity level based on breed, personality, and environment.


At 5 months old, a cat is transitioning from being a kitten to an adult. Their dietary needs are changing during this growth stage. According to Feeding Guidelines for Your Cat – Iams, kittens should be fed three times a day until they are 4 months old. After that, they recommend transitioning to feeding twice a day as the cat approaches adulthood.

So a 5 month old cat may still need more frequent feedings than an adult cat. Their caloric needs are also higher than an adult cat’s, as they are still growing and developing. According to Nutrition – General Feeding Guidelines for Cats – VCA Hospitals, growth is almost complete by 6 months of age. An adult cat food can be introduced around 8-10 months.

At 5 months, kittens are still growing quickly and need a high-quality kitten formula or all life stages formula to support their development. Gradually transitioning them to adult food over the next several months will ensure they get proper nutrition for their changing needs.


Socialization is crucial for kittens in the first few months of life. According to the ASPCA, the prime socialization period for kittens is between 2 and 7 weeks of age [1]. During this time, kittens learn appropriate social behaviors and become comfortable interacting with other cats and humans. Proper socialization helps kittens grow into well-adjusted adult cats.

In contrast to kittens, adult cats are typically less social and interact less frequently with other cats and humans. Whereas kittens play together frequently and seek out human interaction, adult cats often prefer solitary activities like napping, grooming, and hunting toys. Adult cats may hiss, growl, or swat when bothered by other cats or humans in their space. However, a well-socialized adult cat will still enjoy positive interactions on their own terms.

To ensure proper socialization, kittens should stay with their mother and littermates for at least 8-12 weeks. Interacting with their mother and siblings teaches them appropriate social skills like playing gently and using litterboxes. Kittens should also be gradually introduced to new sights, sounds, smells, people, and other animals during this period. With positive early experiences, kittens grow into friendly, confident cats [2].


At 5 months old, your kitten is reaching adolescence and this is an important time for continuing training [1]. While kittens are still very energetic and playful at this age, their attention span starts to improve, making it a good time to reinforce desired behaviors. Use positive reinforcement, such as treats and praise, to reward good behavior [2].

Focus on litter box training, appropriate scratching, bite inhibition, socialization, and any other behaviors you want your cat to learn. Be patient and consistent. Proper training and socialization at this age will pay off with a well-adjusted, happy cat.


Kittens are very vulnerable to disease during the first few months of life, so maintaining their health is crucial during this time. According to the American Veterinary Medical Association (AVMA), kittens should receive a series of core vaccines starting as early as 6-8 weeks of age and continuing every 2-4 weeks until 16 weeks old (

The initial kitten vaccination series protects against three main diseases: feline viral rhinotracheitis, calicivirus and panleukopenia virus. Kittens may also receive vaccines for rabies, feline leukemia virus, Chlamydophila, Bordetella and feline immunodeficiency virus. It’s important to follow your veterinarian’s recommended schedule to ensure full immunity (

Until they complete their vaccine series around 4 months of age, kittens have very limited immunity and are susceptible to highly contagious and potentially fatal illnesses. It’s critical to avoid exposing kittens to stray cats or taking them to crowded public places before vaccination. Indoor confinement and isolation from other pets is safest during this vulnerable period (


At 5 months of age, kittens still have some special care needs. Their immune systems are still developing, so it’s important to continue vaccinations as recommended by your veterinarian. You’ll also want to monitor the kitten’s eating and litter box habits to ensure they are developing normally. Unlike adult cats, 5 month old kittens need more frequent feedings – about 3-4 times per day. Providing interactive playtime and socialization is also critical at this age. Kittens are very energetic and need adequate outlets for exercise and mental stimulation through play. Be sure to provide scratching posts, cat trees, and toys to keep them entertained. It’s also important to continue working on training basic commands like coming when called, not biting or scratching, and using the litter box consistently. With the proper care and attention, your 5 month old kitten will continue to grow into a healthy, well-adjusted cat.


In conclusion, while a 5 month old kitten may seem grown up compared to when they were a tiny newborn, they are still very much a baby cat in terms of development. At 5 months, kittens are extremely playful, energetic, and rambunctious. They need lots of stimulation and socialization at this age to learn proper behaviors and develop mentally and physically. Make sure to provide them with kitten-formulated food, nutrients, and veterinary care. Kittens at this age are still bonding with their human family and learning about their environment. With the right care and attention, your 5 month old kitten will continue to grow into a healthy, well-adjusted cat.

The key things to remember are that kittens remain in the juvenile stage up to around 10-12 months old. So continue actively training, socializing, and caring for your 5 month old kitten as you would a young baby. Provide proper nutrition, vet checkups, affection, playtime, and cat-proofing of your home. With an attentive and nurturing environment, your kitten will steadily grow out of the baby phase and into an amazing adult cat.

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