Reindeer are baby reindeer when they're born, just like human babies are born as babies. Reindeer are born during the spring months, and they're called calves. Reindeer calves are small, fluffy, and cute, and they're born with spots on their fur. They grow and develop quickly, and they're usually fully grown by the time they're one year old. Reindeer can live for up to 15 years, so they have a long and interesting life cycle.