What makes a bull’s antler grow “weird?”

In Elk Facts by RMEF49 Comments

Antler deformities. Photos seem to come into us pretty regularly of very oddly shaped antlers. Our latest example was sent in by twitter user @detourkid1, who wanted to know what causes this. So we decided to let Tom Toman, RMEF Director of Science and Planning, explain what causes these deformities.

Tom Toman

Antler growth that is out of the norm is usually caused by one of two causes.

Genetics

The first is genetic and is probably the most prevalent, although still unusual. Somehow in the growth of the animal, a different combination of genes line up a bit different than usual. We would seldom know why that would happen, but it is not much different from some of us being 5″8″ tall and others being over 6′. It is the combination of genes from the mother and the father that is passed on to the offspring.

Injury

The other factor which I think much more interesting is caused by injury. It usually happens when the antler is in velvet and a bump into a branch or rock could easily bend the soft velvet and if it does not spring back could easily stay in the new position and grow from there.

In some cases the injury occurs to the area of the antler just above the base (burr) and that can cause the growth after that point to take off in an abnormal direction. In some cases the skull is broken and, if the animal survives that kind of collision, the antler grows out of the base in whatever direction the new position is pointing.

The other injury is the strangest kind in that it is not an injury to the antler or the base but rather an injury to a shoulder or hip that causes the antler to grow in an unusual manner or form. If the injury is on the left side of the animal, the opposite antler (right side) will shows some signs of distortion. It may be a very short antler, an antler with quite a number of points but often quite a bit shorter than normal, or it may just be a knob. I have always found this fascinating but have not found any scientific papers that go into this phenomenon.

Hope this helps!

Best regards!