How Old Is My Kitten? [An Illustrated Guide]

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Kittens don't usually come with birth certificates. If you found a stray kitten, or even when adopting from the shelter, you probably don't know your new furry friend's date of birth. Figuring out the age of your kitten can be very important.

Young kittens are fragile and require close monitoring. They need special care where it comes to feeding, cleaning and regulating the temperature of their environment.

So, how can you assess their age? How to tell how old that cute little kitten really is?

The fastest and easiest way to determine the age of a cat is to make a trip to the veterinarian’s office. An experienced rescuer or breeder will also be able to help you estimate the kitten's age. You can also keep reading this guide about the telltale signs of feline early age development to see try and guess the age yourself. And even with all the clues, determining the age of a stray cat is a best-guess effort.

Important note: if you think you may be dealing with newborn kittens, please read this article about hand rearing orphan newborn kittens. Helping such young kittens survive can be extremely challenging. You should probably try to find a local rescuer who's experienced in caring for such young kittens. At the very least, post in this forum and ask for advice. Please do not leave a comment to this article asking for help. Our members simply won't see your questions here. You have to join the forums and post here instead.

But if you're here just to learn more, here's what you need to know about estimating your kitten's age.

Kitten Development Stages - Illustrated Guide

Let's start by looking at how cats develop from birth to adulthood.

Newborn Kittens - the first week

Newborn kittens are born blind and deaf. Their ability to move is limited and they can only maneuver towards their mother's body to suckle and be warm. They cannot regulate their body heat on their own and rely on the mother for warmth, nourishment and protection. Kittens weigh between 80 and 170 grams (2.8-6 ounces) at birth and they can double their body weight during the first week.

One-week-old kittens - the second week

The kittens' eyes open and they begin to process input from the outside world. Their movements gradually become more coordinated but they still stay close to their mother with minimal interaction with their siblings or environment. At the beginning of Week 2, the kittens weigh between 150 and 300 grams (5.3 and 10.5 ounces), with males being slightly heavier on average.

Week 3 in a kitten's life

As their senses develop so do their motor skills, and the kittens stumble around as they learn to walk. They start exploring their environment, and social interaction with siblings begins during this week too. At the beginning of week 3, kittens average 200-400 grams (7-14 ounces).

Four-week-old kittens

While not exactly agile yet, most kittens can walk during the fourth week of their lives, playing with their siblings and with toys too. They also learn to control elimination so it's time to introduce them to a clean and readily available litterbox with non-clumping litter. They may try to taste soft foods now but they still nurse as they weigh 300-500 grams (10.6 ounces - 1.1lbs) at the beginning of week 4 and grow to 350-600 (12 ounces - 1.3 lbs) by the end of the week.

At five to six weeks

During the first half of the second month, kittens are busy critters! They get their teeth and learn how to use them as they discover soft foods while still nursing. They develop their motor skills by climbing, jumping and running around, gradually improving their aim and balance. Social skills develop as well, so make sure they get plenty of human company. Kittens average 500-900 grams (1.1-1.9 lbs) by the end of the sixth week of their lives.

Nearing the two-month mark

As jumping and climbing improve, the kittens increase their range and explore distant areas of the room. Make sure their environment is kitten-proof as they are prone to accidents. They spend their days and nights eating, sleeping and playing with each other, as they learn the ins-and-outs of feline social behavior by testing the limits of their siblings' and mother's patience. They are larger now and most kittens weigh over one kilogram (2.2 lbs) at this point, with males being significantly heavier than females.

Kittens aged 3-4 months

The kittens are more independent now. With their senses and motor skills fully developed, it is their size that prevents them from reaching certain places adult cats can. At 12 weeks of age, they can be safely weaned and go to loving homes. Weighing anything between 1-2.5 kg they are about a third of their final expected body weight.

Kittens aged 5-6 months

The kittens can now be called young cats. They still have a lot of growing to do, as physically they are about half their final expected weight. They lack experience and have a lot to learn. They are full of energy and their curiosity knows no bounds. Now is the right time to have your kitten spayed or neutered and establish household routines that could last throughout their lifetime.

What do kittens' eyes look like as they grow?

When kittens are born, they are blind and their eyes are shut. After about a week or so, they open their eyes. At ten days, the eyes should be fully open.

Eye color is another indicator of a kitten's age. All kittens are born with blue eyes. The color gradually changes as they grow and at as early as seven weeks (in most breeds and mixed breeds), the color begins to change. Some breeds take longer for eye color to become permanent and sometimes, it’s just hard to tell the color—kittens don’t hold still long enough to get a good look!

Read more about your cat's eyes here.

At what age do kittens teeth?

Teeth take their time s Incisors (aka canine teeth or fangs) usually show up at three or four weeks. The lower molars begin to come in at four to five weeks while upper molars show up at about eight weeks. Kittens can eat solid food as early as five weeks. If he’s looking for the food bowl vs. the human putting soft food near his face, it’s a clue that he’s a bit older.

Do kittens lose their baby teeth?

Just like humans, kittens go through two sets of teeth. The first teeth are their temporary "baby teeth". Sometime between the age of six weeks and the age of six months, they gradually lose these smaller teeth and grow a new set that will last them their entire life.

Litter Training

Cats have a natural instinct to dig in the litter when they need to eliminate. That behavior usually starts when the kitten is mobile or at about four weeks. Make sure there's a litter box available to these tiny felines. It should be smaller than a regular box, and with lower sides, so they can easily get in and out of the box. And don't worry if they miss the box occasionally, especially if they're playing too far away from the box to run back to it in time.

Read more: How To Train Kittens To Use The Litter Box

How do cats age?

Moving beyond kittens.

Genetics and heredity play an important part in a cat’s life. If as a kitten, there was plentiful food and water, indoor living, and veterinary care, a cat will be larger and healthier than a feral kitten whose mother was malnourished and unable to provide proper nutrition for the kittens.

If a cat is past the cutesy kitten stage but is obviously not fully mature, chances are he’s a year or two old. In human terms, a year-old cat is comparable to a fifteen-year-old teenager which explains the bursts of energy followed by long naps. At age twenty, the cat is geriatric and comparable to a ninety-six-year-old human—even longer naps and rare energy bursts.

As with any other species, cats slow down as they age. Jumping is natural for cats so if the cat you’ve adopted isn’t comfortable jumping onto the bed, chances are he’s older than first thought. Pet steps or a footstool will give him mobility without added stress. With less exercise, comes weight gain as well. A heavier cat can be older too—or being overweight has slowed a normally active cat.

Just like with humans, the saying goes, “Before beginning a diet and exercise program, be sure to be examined by your veterinarian to make sure you’re healthy enough to make the changes needed to lose weight, improve health and gain mobility.”

Indoor cats live much longer than feral, outdoor cats—no predators to avoid, good quality food, fresh water, and a family to call their own, extend a cat’s life. The average indoor cat lives twelve to fifteen years but with constantly improved veterinary care, twenty and even more can now be an attainable goal.

Feline Age vs. Human Age

Cat owners often wonder how their cat compares to humans when it comes to age. Is being 7 years considered old for a cat? How about 14? How old is my cat in human years?

The average lifespan of humans in developed countries is around 80 years old. For cats, it's around 15. However, cats mature faster than humans do, so at the age of six months, a kitten is not as helpless as a toddler would be at the age of three. Here's an infographic that can give you an idea about your own cat:

So, is 7 considered old for a cat? If by "old" you mean elderly, then not just yet. Most cats can still be considered as being in the prime of their life at that age. However, many veterinarians consider cats to be elderly or "seniors" at 8-10 years. Any older, and your cat can officially be considered an "old-timer".

Just like with people, individual cats age at different rates regardless of their biological age. Talk to your veterinarian and work out an adequate care routine that works for your kitty.

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