A friend of mine who has recently become an expert on reindeer tells me that male reindeer shed their antlers in the autumn, and female reindeer shed their antlers in the spring. Pictures of Santa Claus and his reindeer that I have seen always show them with antlers, so they must be female.
Why does he prefer female reindeer? Does his most famous reindeer, Rudolf, know that she is female?
The Dawn Treader - Richard's Cabin 