According to the Alaska Department of Fish and Game,
while both male and female reindeer grow antlers in the
summer each year, 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
Rudolph to Blitzen- had to be a girl.
We should've known. Only women would be able to drag a
fat-ass man in a red velvet suit all around the world in one
night and not get lost.