Hares and rabbits are in the same family and order, but they are very different.
Rabbits are born completely naked; they have closed eyes and are born deaf. In the wild, they are born in burrows under the ground. By two weeks they can hear, are completely furred, and have their eyes open. They also begin accompanying Mom out of the burrow to help forage and nibble on grass. Adult rabbits stay with the group and become part of the large family, living in the warren with their parents, aunts, uncles and cousins.
Hares are born above ground in a nest of grass and Mom's fur. They have fur, open eyes and can hear immediately after the birth. They stay hidden and Mom brings them food/lets them nurse until they leave the nest and leave their family themselves at only a few weeks old. At a couple months old, they are old enough to start their own families.