Reindeer are real animals that exist in the wild, primarily in the Arctic tundra regions of Europe, Asia, and North America. They are a type of deer with large, broad antlers that they use for defense and attracting mates. Reindeer are also domesticated and used as pack animals by humans for transportation and herding other animals. In many cultures, reindeer are associated with the holiday season due to their association with Santa Claus and his sleigh.