When the story of Rudolph first came out in 1939 it was almost written so that he would be Rudolph the Red stomach/tummy reindeer... but that didn't sit well with author Robert L. May's 5-year-old daughter so the small booklet of "Rudolph the Red Nosed Reindeer" came to be and was given away to children at the Montgomery Ward department store in Chicago. almost 10 years later it would become a popular song, sang by Gene Autry. https://youtu.be/nZeyY0NSTW4 https://www.npr.org/.../the-history-of-rudolph-the-red...
Original source can be found here.