The Growth Stages of a Kitten
After a kitten is born it is goes through several distinct stages of growth that can be timed almost to the day and that are landmarks in its physical, mental and social development.
On average, a newborn kitten weighs about 3 ounces. Each day it gains about a half an ounce muscle, bone and other tissues to do with the development of organs and body systems.
Like human babies, kittens are born with blue eyes that change color. However (unlike human babies) they are born with their eyes closed. Around the 7th to 14th day, the kitten's eyes open. It is normal for one eye to open first and be open before the other for as long as a week. Usually both of the kitten’s eyes are fully functional by the time the cat is two weeks old.
When born, the kitten’s outer ears appear to be flat against the head. In the second or third week, the kitten's outer ears, which have been flat and look like little buds, straighten up and start to look more triangular in shape.
By the third week, the kitten begins to crawl, gradually learning to straighten out his or her legs. By the fourth or fifth week, the kitten is walking and prancing around and has developed enough curiosity as well as mobility skills to explore the environment. At this stage, the mother cat usually teaches her kittens how to use the litter box.
By the sixth week, the kitten can finally retract its claws. They are born with the claws extended. A six-week-old kitten will already have keen sense of smell and sight. At this time, the kitten will also start serious playing and grooming.
The sixth week is also the week when the kitten's baby teeth grow in. This is a clear cue that the kitten is ready for a more meaty solid diet. Kittens who bite are merely teething.
At 8 weeks of age, kittens will start to lose the natural immunities they have received from suckling their mother's milk. This is the best time to begin vaccinating them, and will allow their own immune systems to mount a proper response to the vaccinations.
At around 10 to 12 weeks of age, the blue kitten eye color gradually settles towards the permanent eye color. However, this can vary tremendously with each kitten, and his or her full eye color pigmentation may not be achieved until the kitten is from 1 to 2 years old.
At four months of age, the kitten may begin "teething" again as she will begin to lose her baby teeth and grow her permanent ones, a process which will continue until the age of eight months.
The kitten can officially be called a "teenager" from the age of 6 months to 1 year, and by the eighth month, this teenager is sexually mature and will have behaviors such as calling, mounting and possibly spraying (even females can spray when they are kept whole). This is why it is very important that to have your female spayed or your male neutered at around 4 months old before they start displaying sexually mature behavior.