my yearly reindeer rant: both male and female reindeer grow antlers in the summer each year but male reindeer drop their antlers at the beginning of winter, usually late November to mid December. Female reindeer retain their antlers till after they give birth in the spring. Therefore, according to every historical rendition depicting Santa's reindeer, every single one of them, from Rudolf to Blitzen ... has to be a female.
Although antlers may be considered a masculine symbol, goddesses and female shamans wear them. Deer women appear throughout world mythology. Bendis, Artemis, Elen of the Ways, Satet, and many reindeer goddesses. Female reindeer, btw, have antlers and they are among humanity's oldest deities. (For the less spiritual, you can just enjoy this photo as a sexy Hannibal cosplay.)
"There is also great wealth of sacred[/honored] & magical[/filled with wonder] imagery surrounding the female reindeer & deer in Celtic mythology which often feature tales of white hinds (doe) which are associated with the goddess (who often gives birth to a sun child in the form of a white hind). Fairytales tell us she was ridden by the Snow Queen & peoples of the fairy world."
In the old nature religion (in which the divine was often perceived as feminine) it was the female horned reindeer who reigned supreme as the great goddess of the winter solstice. http://gathervictoria.com/2014/12/04/doe-a-deer-a-female-deer-the-spirit-of-mother-christmas/
The Swimming Reindeer is the name given to a 13,000 year old (Magdalenian) sculpture of two swimming reindeer conserved in the British Museum. The sculpture was made in France by carving the tip of a mammoth tusk. ...there are ten deeper cuts on each side of the back of the leading female reindeer. These may have been intended to indicate coloured markings, but their purpose is unclear.