What is the fur on antlers called?

Antlers don't have fur. They are made of bone and covered in a layer of skin called velvet. This velvet is covered in fine hairs, but it's not true fur.

The velvet helps to nourish the growing antler and provides blood supply. Once the antler is fully grown, the velvet peels off, leaving behind the polished, bony structure we typically associate with antlers.