When kittens are born, their ear canals and eyes are closed.
Kittens' blue-grey eyes often change to a more stable coloration after a year of life.
Kittens get antibodies and nutrition from their mother's colostrum.
Most mothers will lick their kittens to encourage them to urinate and defecate.
Kittens develop a vomeronasal organ at 4 weeks and have excellent hearing and smell.
Kittens don't start walking at three weeks of age, but they do begin to run and play the week after that.
If the mother mates with more than one male, her kittens may not all have the same father.
Kittens must be fed every 2-3 hours, making bottle-feeding difficult.
Cats knead their paws to stimulate milk flow during breastfeeding and for comfort when older.
Fleas can spread diseases to kittens, who can't use flea creams.