By now you have no doubt heard the obligatory Rudolph the Red Nosed Reindeer song 10 times on the radio or department store sound systems. The assumption is that because Rudolph is depicted with antlers that he’s a he, and that may be correct. But if you will allow me some natural history holiday fun, it possible that Rudolph was a her.

Okay, let’s talk antlers. They are of course those spiky things growing out of the heads of members of the deer family, whom science guys call Cerviadae. The family includes deer, elk, moose, and our topic the reindeer, also known as caribou in North America. Antlers are extensions of the animal’s skull, and made of true bone. They are grown by the males each year and then shed off, and their function is sexual. Their size is attractive to females, and they are used as weapons to fight off other male suitors.

Reindeer however, are the exception, with both the male and female growing antlers. The likely reason is that the antlers are not only used in the procreation process, but also used to clear away snow to reach vegetation to eat. Females also use them fend off threats and defend feeding area, which in snow country is critical.

So now we come to it. Once the reindeer cows are pregnant, the bull’s testosterone level drops, triggering changes that make the antlers fall off, which normally takes place in November or early December. This suggests that reindeer with antlers on Christmas Eve are female. But it turns out that young adolescent males keep theirs a little longer, so it’s indeed possible that Rudolph could be a young male, as the song and cartoon suggests. But the older reindeer on Santa’s sleigh pulling team could very well be females…. and pregnant. Just saying.

Steve Roark is the area forester in Tazewell, Tennessee, for the Tennessee Department of Agriculture, Forestry Division.