There are more and more stray cats outside. Many caring people will choose to adopt and go home or give out cat food regularly. How to judge the age of a kitten is helpful to the feeding and growth of cats. So, we can use the simplest method to determine the age of kittens. 1. Umbilical cord: if you see a kitten whose umbilical cord has not fallen off, it should not be more than three days. 2. Eyes: Generally speaking, kittens open their eyes in about 10 days, which is an average number. 3. Ears: at birth, the ear canal is closed. It starts to open on the 5th to 8th day. It can stand up in 15-20 days. 4. Teeth: the order of long teeth is: front teeth (10-15 days), canine teeth (15-25 days), and grooved teeth (30-40 days). Finally, it is suggested that if the milk of a sucking cat does not have the milk from the mother cat to supply its physiological nutrition, it is necessary to pay attention not to feed milk from the middle of the cat’s mouth during artificial feeding, so as to avoid choking death.