Kitten age can be difficult to determine if a kitten is found after birth, but is important to know so that the kitten can receive the proper amount of care. A vet or animal care expert may be the most accurate resource to turn to when trying to determine the age of a kitten, but there are a few steps that a cat owner can take to try and guess a kitten's age.
Look for Umbilical Cord
The smallest kittens will still have their umbilical cords attached. Kitten age on a kitten with an umbilical cord is as young as zero to three days. It's essential that the kitten receive round-the-clock care at this age if she's been separated from her mother—preferably with a foster mother cat.
Check on the Status of Her Eyes and Ears
Kitten age can also be determined by looking at the kitten's eyes and ears. Kittens will begin partially opening their eyes at about one week to ten days old. Their eyes will completely open and their ears will begin to open at between two to three weeks of age. Kittens typically have blue eyes for the first two weeks of life and their eyes change color afterward. However, some cats, particularly all white cats and Siamese cats, do retain their blue eye color.
Watch Her Level of Activity
Kittens do not even begin to stand until they are between two and three weeks of age. They begin to become more explorative at around four weeks of age, but they may still stumble a lot. At around five weeks, kittens tend to stumble less often. Kitten age can be difficult to determine via level of activity after six weeks, as the kittens will become extremely playful and active afterward and this extra energy can last for between eight months to a year, when the kitten becomes an adult cat.
Check Her Teeth
A kitten will have all of her baby teeth at around eight weeks of age. This means that she will have incisors, canines, bicuspids and molars. Kitten owners who see no or less than a full mouth worth of teeth can guess her age with the following in mind:
- 0 to 2 weeks: No teeth
- 2 weeks: Incisors (small front teeth) begin to develop
- 3 to 4 weeks: Canines (pointy, long teeth on either side of the front teeth) develop
- 4 to 6 weeks: Bicuspids (the teeth to the other side of the canines) develop
Estimate Her Size
Kittens grow quickly. At the kitten age of between three and four months old, they are already about half the size of an adult cat. Kittens who are even smaller are younger than that. At one year, the kitten is considered an adult and may be fully grown, although it's possible for her to grow a bit bigger over the next year.