Reindeer have also adapted to the cold with extremely insulating coats. In fact, for most of the year, they have a higher risk of overheating than freezing. Each year, reindeer shed a thick winter coat for a summer one and so, counter-intuitively, the only time of the year they may feel cold is in the summer. This means that the issue is therefore about getting rid of heat. Apart from their noses, reindeers are also able to flush their legs with blood, losing heat by radiation.
Reindeer’s distinguishing feature to other deer species is, of course, their antlers; normally only male deer have antlers. All male deer use their antlers to fight for access to females, but female reindeer use their antlers for protecting their calves and defending food. Deer with the largest antlers also tend to be socially dominant and in the best physical shape. Compared to their body size, reindeer also have the largest antlers of any deer type, with the male antlers growing to up to 51 inches. Males grow their antlers in February and drop them in November, and females keep their antlers through the winter until their calves are born in May. And yes, this means that any reindeer with antlers in Christmas are female. Therefore technically, Rudolph with antlers must be female!