Editors Blog

Injury Causes Contralateral Effect in Deer

These amazing videos (below) show just how exactly a traumatic injury to a white-tailed deer can lead to what deer biologists call “the contralateral effect” in a whitetail buck.

Whitetail oddities run in all sorts of shapes and sizes. One of the most common questions I’ve received over the years here at Deer & Deer Hunting centers on whitetail bucks that have one goofy-looking antler and one “normal” antler.

Contralateral effect in deer

Author Dan Schmidt shot this heavy buck while hunting in Wisconsin in 2003. The deer’s rack – 5 perfect points on one side and just 2 on the other side — was the result of the contralateral effect. This happens when a deer suffers a major injury to one side of its body. The resulting antler growth causes a mishapen antler to grow on the opposite side of the injury. (photo by Tracy Schmidt)

What Causes Contralateral Effect in Deer?

Many things can cause a giant buck to grow weird antlers, but injuries more often than not are the culprit. There is strong evidence that an injury to a velvet pedicle will cause the deer to grow an abnormal antler on the other side of its head. This is known in the scientific world as the “contralateral effect.”

What essentially happens here is that the buck’s internal chemistry takes over and redirects that energy to other parts of the deer. This is believed to be a survival mechanism. Many times, bucks exhibiting this antler effect will be much larger in the body. That was the case with the buck pictured above. I shot this 4-1/2-year-old buck about 15 years ago, and his is still the heaviest whitetail I have ever killed. He weighed 284 pounds on the hoof. His antler configuration was a clean 5-point side and a 21-inch beam with only a brow tine on the other side. When I skinned this buck, I learned that his right hind leg had suffered a serious wound. Encased in a cyst in that leg was a fist-sized ball of scar tissue. This injury undoubtedly led to the contralateral effect on that opposite antler. Think about this the next time you field dress a deer that might have a similar rack. You just might find the reason behind his antler configuration.

Is the Contralateral Effect Permanent?

I should note that our Deer & Deer Hunting field editors believe the contralateral effect isn’t necessarily a permanent condition. For example, Charles Alsheimer once told me that he had seen several deer recover from this condition and grow normal racks in subsequent years. This, he said, is usually dictated by the extent of the injury. These injuries do not affect the venison.

The first video that we captured was this past April. We aren’t certain, but we believe this deer was hit by an automobile on a nearby county highway. At the time, we weren’t 100 percent sure this was a buck, although we had seen a buck (on trail camera) with a similar injury the previous hunting season:

Video 2 shows that same deer here just a few weeks ago. Notice how his rack has grown in the true definition of “the contralateral effect.”


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