The Birth of a Kitten

Most kittens are born headfirst, but some may be reversed. The average litter consists of four kittens, but there may be only one or as many as seven. They are born one at a time, usually about half an hour apart. Each is enclosed in a thin transparent sac, which the mother immediately breaks and removes with her teeth and tongue. The newborn kitten weighs about 3 1/2 to 5 ounces (100 to 142 grams) and is about 3 inches (8 centimeters) long.

Most cats need little assistance during kittening; however, many are comforted by the presence of their owners. Occasionally the sac will be tough, and the mother may be unable to break it. If this happens, the owner should break it, as the kitten may suffocate.

At birth the kitten has no teeth, the eyes are closed, the ears lie flat against the head, the tail is short and triangular, and the fur is soft and downy. The kitten begins to get its first teeth when it is two or three weeks old, and all 26 of them have grown in by the time it is two months old. These baby teeth are replaced by the 30 permanent teeth when the animal is about six months old.

The eyes begin to open when the kitten is about 8 to 12 days old. All kitten's eyes are blue. It may take several months for the eyes to change to their permanent color.

Source : http://lookd.com/cats/life.html