A remarkable roe deer was shot and killed by a hunter in Slovenia in August of 2014. This species of deer is very common and widespread in Slovenia, but what isn’t common is the deformity which has caused the deer to have only one antler. The hunter claimed to have chosen the deer for its advanced age and single antler; little did he know that the lack of a second antler was due to the deer having only one antler to start with. The assumption of the animals advanced age was made based off of his having only one antler. When a deer gets older it is not uncommon for them to lose an antler and when that happens the antler left intact is referred to as a “spike”.
The hunter had no way of knowing that the deer he was hunting did not actually have a “spike” due to old age, but instead bore the unique deformity.
A scientist told National Geographic that this particular deformity is so rare the he has never seen it occur in nature before. Basically, where the antlers should have come in completely separate of each other, they instead grew together to produce one singular protrusion, giving the dear the appearance of the mythical unicorn. It is likely that the deformity in the growth of the antlers was caused by some kind of injury to the deer’s antlers in the very early stages of development.
As also noted by National Geographic, the deformity does not appear to have hindered the animal in any way during its life, as the deer had reached a very advanced age already and was noted to have am above average weight, when killed.
Though this is the first time a deer with a “unicorn” horn has been killed in the wild, there have been sightings of other deer bearing the same single horn appearance in places like Italy and the United States.
Assumptions can only be made as to the cause for the deformity in these cases as it would be difficult to determine how the single horn grew in abnormally without a body to examine or without performing a necropsy (an autopsy on an animal).