A lamb is a young sheep that has not reached one year of age while a sheep is an adult animal of the same species. Lambs are born with a thick wool coat which is usually sheared when they are about eight months old. Sheep, on the other hand, are covered with a much coarser, longer-haired wool coat which is usually sheared once a year. Lambs are usually born in the spring and are able to move around almost immediately after birth, while ewes, or adult female sheep, are usually pregnant for five months before giving birth. Lambs are usually weaned from their mother’s milk at around three months of age, while sheep can continue to nurse until they are almost a year old.