The technical name for these growths: cutaneous fibromas. They are smooth, black to gray hairless tumors of the skin caused by a virus, which is thought to be transmitted to deer by biting insects, just as blue tongue is transmitted.
Warts may show as single, multiple, or in clumps; they can vary from 1/2 to 8 inches in diameter. They can be found anywhere on a deer, but are most common on the head, neck, and shoulders.
The growths rarely extend below the hide of a deer. When the skin from a deer with warts is removed there is typically no evidence of any problem with the meat. Biologists say only large tumors that become infected with secondary bacterial infection would cause a deer to be unfit for human consumption.
Growths like these are not all that uncommon on whitetail deer in the summer. But I have spent more than 40 years observing and hunting deer and have never seen an animal like this. Have you ever seen a deer with warts?