What happened to Dasher then? Plus the spelling of donna (sic) is wrong...it's donner who along with blitzen of course makes up the german term (loosely) for thunder and lightning.
And they were all female! All male reindeer lose their antlers at the beginning of winter so by Christmastime only the females have antlers. I vaguely knew this to be the case but it was confirmed on QI last night
That'll teach me to read the answer first, there are actually nine reindeer, four pairs and Rudolph. The pairs being, Dasher & Dancer, Prancer & Vixen, Comet & Cupid, Donner & Blitzen