
Kitten Development Stages: Must-Knows About Newborn Kitten Development
Kitten Development Stages: Must-Knows About Newborn Kitten Development
Kitten how old? Every year when Spring rolls around we celebrate kitten season! On July 10, we celebrate National Kitten Day, so if a new baby is in your plans, here’s some kitten care info. If you love kittens, learning about newborn kitten development, when kitten eyes open, and more, helps you know what to expect, and help the baby along the way.
Even if it’s not yet kitten season, it’s helpful to figure out the best age to adopt kittens. Read on to learn about the cat behavior of a three-week-old baby compared to one six weeks old. So whatever time of year, prepare now with all your kitten questions so you’re ready when the purr-fect cat or kitten becomes available.
Kitten Season Brings Roaming Cats
Cats are considered kittens until about one year of age. Before that, though, the girl kitties can become pregnant. It’s not unusual for the unwanted youngsters to roam, looking for someplace safe. That’s how we found Karma-Kat. He showed up in late January, just before an ice storm hit. At age 8 months or so, his “cute” had worn off, and somebody lost him either accidentally or on purpose. Their loss, and our gain.
Cat Development Stages
In the Northern hemisphere, intact girl kitties begin to go into heat in February, and can become pregnant as early as four or five months of age. Within about 63 days, new furry babies make their appearance so brace yourselves for a bumper crop of cute-icity.
Kittens gain two to four ounces a week from birth to five to six months of age. The kitten immune system becomes fully developed by six to eight weeks of age, while the immune protection he gained from Mom begins to fade.
Kitten How Old? Here are Kitten Development Stages
At Birth
When your kitten was born, he measured four to six inches long and weighed only two to four ounces. He was blind, deaf, toothless, and unable to regulate his own body temperature to stay warm. Newborns are able to maintain only 95 degree temperature (normal adult temp is 100-102.5) so they must be in contact with Mom or surrogate warmth to survive. At this age, kittens depend on touch, sense of smell, and thermal sensation to find Mom and food, and they move by wriggling their bodies from side to side. Babies purr as they nurse, and most return to the same nipple every time. That’s because they scent-mark the nipple the first time they nurse and the smell acts as a beacon to draw them back thereafter.
Week One
After seven days, the kitten’s birth weight doubles. Kittens spend four hours a day suckling, and more than 16 hours sleeping. Instead of moving like little worms, their shoulders, pelvis and legs develop enough so they can drag themselves along the ground. They look a bit like swimmers paddling across the bedding. By this age, the body’s shiver reflex develops, and that means they are better able to regulate temperature and keep themselves warm.
Week Two
By the second week, kittens suckle up to three hours a day. Their eyes begin to open between nine to 12 days of age, and babies learn to recognize Mom and others as friends or foe. Ears begin to unseal about this same time. Kittens practice raising their chest with front legs, and strengthen their muscles by moving about more. And the first deciduous (baby or milk) teeth start to appear at this age, the tiny incisors across the front of the mouth.
Week Three
Nursing time starts to decrease, but the babies still suckle about two hours a day. The rear legs gain strength and kittens start to stand and walk on wobbly legs. The sense of smell becomes fully developed, and the babies begin to catalogue the meaning of different scents. Kittens start to play with each other, follow Mom around, learn about the litter box, and can retract their claws. They start to watch Mom and mimic her by self-grooming themselves. Body temperature control develops. Normal body temperature increases to between 97 to 99 degrees during this period. The prime socialization period begins. What kittens experience beginning at this age will have a huge impact on how well-adjusted (or not) they become as adults. Kittens handled a few minutes daily by people during their first month of life have an improved learning ability.
Week Four
Kitten hearing is fully developed by week four, and the body weight has doubled again. Mom’s milk production starts to decrease just as the kitten’s energy needs grow. Curiosity and hunger spur the babies to sample Mom’s solid food. Kkittens understand the litter box from watching Mom. However, they still have a limited capacity for “holding it” and may have accidents when the box isn’t close enough. Needle sharp canine teeth appear next to the incisors, and premolars grow behind the canines (three on the top, two on the bottom).
Week Five to Seven
The body thermostat has matured enough the kitten doesn’t rely on Mom or siblings to stay warm. The kitten immune system fully developes by six to eight weeks of age, while the immune protection he gained from Mom begins to fade. It takes six to eight weeks for the last premolars to erupt. The drive to copy Mom is very strong, and they learn what they should do by imitating her. Kittens spend nearly an hour a day eating solid food—but they’ll still pester Mom to nurse, if she’ll let them.
Kittens learn to recognize friends and enemies. Good experiences with people and other pets during this time ensure they’ll be well-adjusted adult cats.
Week Eight to Nine
Kittens are fully weaned and eating a commercial kitten food. They spend up to an hour each day in play—and switch from playing with each other, to playing with objects—toys, feathers, etc. That strengthens muscles, practices social skills, and teaches life lessons by learning to inhibit bites and claws, discover what rolls or bounces when patted with a forepaw, and what runs away or fights back.
Month Three to Six
Social play reaches its peak between week nine through week 16. Older kittens and adult cats continue to play after four months, but not to the same extent. Baby teeth start to fall out at 12 weeks and are replaced by permanent adult teeth. A total of 30 adult teeth are present in most cats by age seven months.
Female kittens may experience their first breeding season (heat) and may become pregnant as early as four months of age, but most reach this point at five to six months of age. “Oriental” breeds like Siamese tend to become fertile at an earlier age.
Month Nine to Twelve
Male kittens become sexually mature and are able to father babies as early as eight to nine months, and develop male-cat behaviors like spraying as early as six to seven months (average age is nine months). Both sexes continue to fill out and gain weight. Coats on longhaired breeds like Maine Coon and Persian cats may not fully develop until they are 15 to 18 months old.
Kitten Development Stages & Nonstop Kitten Play
Play and interaction with others takes over during weeks five to seven. Social play with Mom and siblings begins now, and includes running, rolling, biting, wrestling, climbing, and jumping. Mom-cat and siblings let the baby know if he bites or claws too hard and they’ll hiss at him or put an end to the game. If you want to avoid kittens chasing your feet, adopt a pair together! Otherwise, you’ll need to deal with kitten play aggression. Learn more about fostering kittens with socialization tips here.

Handraised newborn kittes need to be fed every 4 hours or so with an appropriate kitten milk replacement.
Kitten Development Stages & Ideal Adoption Age
When kittens are adopted too early, or are orphaned and hand raised, you’ll have extra challenges to bringing up baby. By watching mom, kittens learn to use the litter box, for example. What’s cute in a tiny kitten becomes aggravating or even dangerous when he gets older and can tip playtime into play aggression.
Adopting a pair of kittens can be a good option, so the babies wrestle and play with each other rather than targeting your ankles. If you also have dogs, read about introducing your cat to dogs here. Learn more about cat-to-cat introductions here. If you are the “mother figure” it’s up to you to teach Baby about the litter box, playing “nice” and eating grown-up food. Learn more about kitten adoption do’s and don’ts here.
Kitten Socialization For A Lifetime of Love

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Puppies get more attention when it comes to socialization and puppy developmental stages are a bit different. But socialization is equally important in kittens. The problem is–prime kitten socialization takes place between two-to-seven weeks of age! Oh, the baby will learn after that, but his is the best time to pre-program a cat for success. When you adopt a kitten at this age, it’s up to you to expose him to a wide range of situations so he’ll be willing to accept them as he ages. That’s called “socialization” and can mean the difference between living with a well-adjusted and loving feline, or dealing with a scared or aggressive cat.
Good experiences with people and other pets during this time ensure they’ll be well-adjusted adult cats. It’s ideal for kittens to stay with their littermates and mother until twelve weeks of age so they learn best how to get along with other cats, and learn all the important “cat rules” of the world. But very often, shelters need the space and adopt out babies earlier–or the kitten is alone in the world anyway, and benefits from being adopted earlier.
It’s important to have handy all the important kitten info. So if you’ve read this far, here’s an EBOOK deal for you–a discounted copy of COMPLETE KITTEN CARE by clicking here.
TEACH KITTENS NOW TO ACCEPT…
Handling and grooming by you and strangers teaches him to accept such things, so the veterinarian won’t have to fight him for an examination. This is the best age to train him to accept the cat carrier and leash. That allows him to travel with you when necessary, either to the vet or groomers or across town to visit Grandma. And if you think another pet (dog or cat), or a child might be in your future, introduce him to positive experiences at this age. That way, he’ll accept them as a normal part of his world and you’ll prevent behavior problems down the road.
How old was your cat when you adopted him? Have you ever needed to hand-raise a kitten? What do you think is the best age to adopt–and why? Please share!
I love hearing from you, so please share comments and questions. Do you have an ASK AMY question you’d like answered? Do you have a new kitten and need answers? Stay up to date on all the latest just subscribe the blog, “like” me on Facebook, and sign up for Pet Peeves newsletter. Stay up to date with the latest book giveaways and appearances related to my September Day pet-centric THRILLERS WITH BITE!
Amy Shojai, CABC is a certified cat & dog behavior consultant, a consultant to the pet industry, and the award-winning author of 35+ pet-centric books and Thrillers with Bite! Oh, and she loves bling!