Rudolf and his red nose is a late edition to Santa's sleigh pulling team (created in 1939 by department store copywriter Robert L. May) and is almost certainly the only male reindeer in the bunch. How so?
We reckon that savvy Santa wisely opted for an all-girl sled-pulling squad on purpose. Even though they are mythical reindeer we’re talking about, there’s actual evidence to support the 'girls only' reindeer theory. It’s mostly about the antlers.
Did you know that male reindeer shed their antlers in early December? Females retain their headgear all winter long. In pretty much every depiction of St. Nick making his Christmas Eve run, the team pulling his sleigh are sporting antlers, ergo, said reindeer are female.
Another clue is that the names of Santa's reindeer are not gender specific: Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner, and Blitzen. The exception, of course, is Rudolf - a copywriter's later fictional addition.
To top this off, there’s an eminently practical reason for Santa to hitch his harnesses to an all-female team: Female reindeer have about a 45 percent greater fat-to-body-mass ratio than their male counterparts. This extra tissue serves as insulation that keeps them warm in frigid conditions as low as minus 45 degrees Fahrenheit (minus 43 degrees Celsius), and baby, it’s cold outside - especially in the upper atmosphere. We rest our case!